1 | /*
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2 | * Copyright (c) 2018 Jaroslav Jindrak
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | *
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9 | * - Redistributions of source code must retain the above copyright
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10 | * notice, this list of conditions and the following disclaimer.
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11 | * - Redistributions in binary form must reproduce the above copyright
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12 | * notice, this list of conditions and the following disclaimer in the
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13 | * documentation and/or other materials provided with the distribution.
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14 | * - The name of the author may not be used to endorse or promote products
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15 | * derived from this software without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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27 | */
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28 |
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29 | #ifndef LIBCPP_INTERNAL_MEMORY_SHARED_PTR
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30 | #define LIBCPP_INTERNAL_MEMORY_SHARED_PTR
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31 |
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32 | #include <exception>
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33 | #include <internal/functional/arithmetic_operations.hpp>
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34 | #include <internal/memory/allocator_arg.hpp>
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35 | #include <internal/memory/shared_payload.hpp>
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36 | #include <type_traits>
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37 |
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38 | namespace std
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39 | {
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40 | template<class T>
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41 | class weak_ptr;
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42 |
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43 | /**
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44 | * 20.8.2.1, class bad_weak_ptr:
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45 | */
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46 |
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47 | class bad_weak_ptr: public exception
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48 | {
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49 | public:
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50 | bad_weak_ptr() noexcept = default;
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51 |
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52 | const char* what() const noexcept override
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53 | {
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54 | return "std::bad_weak_ptr";
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55 | }
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56 | };
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57 |
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58 | /**
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59 | * 20.8.2.2, class template shared_ptr:
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60 | */
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61 |
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62 | template<class T>
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63 | class shared_ptr
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64 | {
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65 | public:
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66 | using element_type = T;
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67 |
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68 | /**
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69 | * 20.8.2.2.1, constructors:
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70 | */
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71 |
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72 | constexpr shared_ptr() noexcept
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73 | : payload_{}, data_{}
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74 | { /* DUMMY BODY */ }
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75 |
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76 | template<class U>
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77 | explicit shared_ptr(
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78 | U* ptr,
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79 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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80 | )
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81 | : payload_{}, data_{ptr}
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82 | {
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83 | try
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84 | {
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85 | payload_ = new aux::shared_payload<T>{ptr};
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86 | }
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87 | catch (const bad_alloc&)
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88 | {
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89 | delete ptr;
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90 |
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91 | throw;
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92 | }
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93 | }
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94 |
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95 | template<class U, class D>
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96 | shared_ptr(
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97 | U* ptr, D deleter,
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98 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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99 | )
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100 | : shared_ptr{}
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101 | {
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102 | try
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103 | {
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104 | payload_ = new aux::shared_payload<T, D>{ptr, deleter};
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105 | }
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106 | catch (const bad_alloc&)
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107 | {
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108 | deleter(ptr);
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109 |
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110 | throw;
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111 | }
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112 | }
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113 |
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114 | template<class U, class D, class A>
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115 | shared_ptr(
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116 | U* ptr, D deleter, A,
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117 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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118 | )
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119 | : shared_ptr{}
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120 | {
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121 | try
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122 | {
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123 | payload_ = new aux::shared_payload<T, D>{ptr, deleter};
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124 | }
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125 | catch (const bad_alloc&)
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126 | {
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127 | deleter(ptr);
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128 |
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129 | throw;
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130 | }
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131 | }
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132 |
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133 | template<class D>
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134 | shared_ptr(nullptr_t ptr, D deleter)
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135 | : shared_ptr{}
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136 | { /* DUMMY BODY */ }
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137 |
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138 | template<class D, class A>
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139 | shared_ptr(nullptr_t, D deleter, A)
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140 | : shared_ptr{}
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141 | { /* DUMMY BODY */ }
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142 |
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143 | template<class U>
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144 | shared_ptr(
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145 | const shared_ptr<U>& other, element_type* ptr,
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146 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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147 | )
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148 | : payload_{other.payload_}, data_{ptr}
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149 | {
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150 | if (payload_)
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151 | payload_->increment();
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152 | }
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153 |
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154 | shared_ptr(const shared_ptr& other)
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155 | : payload_{other.payload_}, data_{other.data_}
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156 | {
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157 | if (payload_)
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158 | payload_->increment();
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159 | }
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160 |
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161 | template<class U>
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162 | shared_ptr(
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163 | const shared_ptr<U>& other,
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164 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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165 | )
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166 | : payload_{other.payload_}, data_{other.data_}
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167 | {
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168 | if (payload_)
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169 | payload_->increment();
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170 | }
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171 |
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172 | shared_ptr(shared_ptr&& other)
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173 | : payload_{move(other.payload_)}, data_{move(other.data_)}
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174 | {
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175 | other.payload_ = nullptr;
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176 | other.data_ = nullptr;
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177 | }
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178 |
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179 | template<class U>
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180 | shared_ptr(
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181 | shared_ptr<U>&& other,
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182 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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183 | )
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184 | : payload_{move(other.payload_)}, data_{move(other.data_)}
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185 | {
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186 | other.payload_ = nullptr;
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187 | other.data_ = nullptr;
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188 | }
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189 |
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190 | template<class U>
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191 | explicit shared_ptr(
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192 | const weak_ptr<U>& other,
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193 | enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
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194 | )
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195 | {
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196 | if (other.expired())
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197 | throw bad_weak_ptr{};
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198 | // TODO:
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199 | }
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200 |
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201 | template<class U, class D>
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202 | shared_ptr(
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203 | unique_ptr<U, D>&& other,
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204 | enable_if_t<
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205 | is_convertible_v<
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206 | typename unique_ptr<U, D>::pointer,
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207 | element_type*
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208 | >
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209 | >* = nullptr
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210 | ) // TODO: if D is a reference type, it should be ref(other.get_deleter())
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211 | : shared_ptr{other.release(), other.get_deleter()}
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212 | { /* DUMMY BODY */ }
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213 |
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214 | constexpr shared_ptr(nullptr_t) noexcept
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215 | : shared_ptr{}
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216 | { /* DUMMY BODY */ }
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217 |
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218 | /**
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219 | * 20.8.2.2.2, destructor:
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220 | */
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221 |
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222 | ~shared_ptr()
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223 | {
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224 | remove_payload_();
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225 | }
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226 |
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227 | /**
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228 | * 20.8.2.2.3, assignment:
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229 | */
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230 |
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231 | shared_ptr& operator=(const shared_ptr& rhs) noexcept
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232 | {
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233 | if (rhs.payload_)
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234 | rhs.payload_->increment();
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235 |
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236 | remove_payload_();
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237 |
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238 | payload_ = rhs.payload_;
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239 | data_ = rhs.data_;
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240 |
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241 | return *this;
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242 | }
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243 |
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244 | template<class U>
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245 | enable_if_t<is_convertible_v<U*, element_type*>, shared_ptr>&
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246 | operator=(const shared_ptr<U>& rhs) noexcept
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247 | {
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248 | if (rhs.payload_)
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249 | rhs.payload_->increment();
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250 |
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251 | remove_payload_();
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252 |
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253 | payload_ = rhs.payload_;
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254 | data_ = rhs.data_;
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255 |
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256 | return *this;
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257 | }
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258 |
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259 | shared_ptr& operator=(shared_ptr&& rhs) noexcept
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260 | {
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261 | shared_ptr{move(rhs)}.swap(*this);
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262 |
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263 | return *this;
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264 | }
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265 |
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266 | template<class U>
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267 | shared_ptr& operator=(shared_ptr<U>&& rhs) noexcept
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268 | {
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269 | shared_ptr{move(rhs)}.swap(*this);
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270 |
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271 | return *this;
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272 | }
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273 |
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274 | template<class U, class D>
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275 | shared_ptr& operator=(unique_ptr<U, D>&& rhs)
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276 | {
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277 | shared_ptr{move(rhs)}.swap(*this);
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278 |
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279 | return *this;
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280 | }
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281 |
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282 | /**
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283 | * 20.8.2.2.4, modifiers:
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284 | */
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285 |
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286 | void swap(shared_ptr& other) noexcept
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287 | {
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288 | std::swap(payload_, other.payload_);
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289 | std::swap(data_, other.data_);
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290 | }
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291 |
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292 | void reset() noexcept
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293 | {
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294 | shared_ptr{}.swap(*this);
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295 | }
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296 |
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297 | template<class U>
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298 | void reset(U* ptr)
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299 | {
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300 | shared_ptr{ptr}.swap(*this);
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301 | }
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302 |
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303 | template<class U, class D>
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304 | void reset(U* ptr, D deleter)
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305 | {
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306 | shared_ptr{ptr, deleter}.swap(*this);
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307 | }
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308 |
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309 | template<class U, class D, class A>
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310 | void reset(U* ptr, D deleter, A alloc)
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311 | {
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312 | shared_ptr{ptr, deleter, alloc}.swap(*this);
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313 | }
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314 |
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315 | /**
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316 | * 20.8.2.2.5, observers:
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317 | */
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318 |
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319 | element_type* get() const noexcept
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320 | {
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321 | return data_;
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322 | }
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323 |
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324 | enable_if_t<!is_void_v<T>, T&> operator*() const noexcept
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325 | {
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326 | return *data_;
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327 | }
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328 |
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329 | T* operator->() const noexcept
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330 | {
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331 | return get();
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332 | }
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333 |
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334 | long use_count() const noexcept
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335 | {
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336 | if (payload_)
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337 | return payload_->refs();
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338 | else
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339 | return 0L;
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340 | }
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341 |
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342 | bool unique() const noexcept
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343 | {
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344 | return use_count() == 1L;
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345 | }
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346 |
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347 | explicit operator bool() const noexcept
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348 | {
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349 | return get() != nullptr;
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350 | }
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351 |
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352 | template<class U>
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353 | bool owner_before(const shared_ptr<U>& ptr) const
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354 | {
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355 | return payload_ < ptr.payload_;
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356 | }
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357 |
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358 | template<class U>
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359 | bool owner_before(const weak_ptr<U>& ptr) const
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360 | {
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361 | return payload_ < ptr.payload_;
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362 | }
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363 |
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364 | private:
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365 | aux::shared_payload_base<element_type>* payload_;
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366 | element_type* data_;
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367 |
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368 | shared_ptr(aux::payload_tag_t, aux::shared_payload_base<element_type>* payload)
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369 | : payload_{payload}, data_{payload->get()}
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370 | { /* DUMMY BODY */ }
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371 |
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372 | void remove_payload_()
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373 | {
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374 | if (payload_)
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375 | {
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376 | auto res = payload_->decrement();
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377 | if (res)
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378 | payload_->destroy();
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379 |
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380 | payload_ = nullptr;
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381 | }
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382 |
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383 | if (data_)
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384 | data_ = nullptr;
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385 | }
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386 |
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387 | template<class U, class... Args>
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388 | friend shared_ptr<U> make_shared(Args&&...);
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389 |
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390 | template<class U, class A, class... Args>
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391 | friend shared_ptr<U> allocate_shared(const A&, Args&&...);
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392 |
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393 | template<class D, class U>
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394 | D* get_deleter(const shared_ptr<U>&) noexcept;
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395 |
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396 | template<class U>
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397 | friend class weak_ptr;
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398 | };
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399 |
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400 | /**
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401 | * 20.8.2.2.6, shared_ptr creation:
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402 | * Note: According to the standard, these two functions
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403 | * should perform at most one memory allocation
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404 | * (should, don't have to :P). It might be better
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405 | * to create payloads that embed the type T to
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406 | * perform this optimization.
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407 | */
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408 |
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409 | template<class T, class... Args>
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410 | shared_ptr<T> make_shared(Args&&... args)
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411 | {
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412 | return shared_ptr<T>{
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413 | aux::payload_tag,
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414 | new aux::shared_payload<T>{forward<Args>(args)...}
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415 | };
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416 | }
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417 |
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418 | template<class T, class A, class... Args>
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419 | shared_ptr<T> allocate_shared(const A& alloc, Args&&... args)
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420 | {
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421 | return shared_ptr<T>{
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422 | aux::payload_tag,
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423 | new aux::shared_payload<T>{allocator_arg, A{alloc}, forward<Args>(args)...}
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424 | };
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425 | }
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426 |
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427 | /**
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428 | * 20.8.2.2.7, shared_ptr comparisons:
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429 | */
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430 |
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431 | template<class T, class U>
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432 | bool operator==(const shared_ptr<T>& lhs, const shared_ptr<U>& rhs) noexcept
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433 | {
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434 | return lhs.get() == rhs.get();
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435 | }
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436 |
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437 | template<class T, class U>
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438 | bool operator!=(const shared_ptr<T>& lhs, const shared_ptr<U>& rhs) noexcept
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439 | {
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440 | return !(lhs == rhs);
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441 | }
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442 |
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443 | template<class T, class U>
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444 | bool operator<(const shared_ptr<T>& lhs, const shared_ptr<U>& rhs) noexcept
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445 | {
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446 | return less<common_type_t<T*, U*>>{}(lhs.get(), rhs.get());
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447 | }
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448 |
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449 | template<class T, class U>
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450 | bool operator>(const shared_ptr<T>& lhs, const shared_ptr<U>& rhs) noexcept
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451 | {
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452 | return rhs < lhs;
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453 | }
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454 |
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455 | template<class T, class U>
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456 | bool operator<=(const shared_ptr<T>& lhs, const shared_ptr<U>& rhs) noexcept
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457 | {
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458 | return !(rhs < lhs);
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459 | }
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460 |
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461 | template<class T, class U>
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462 | bool operator>=(const shared_ptr<T>& lhs, const shared_ptr<U>& rhs) noexcept
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463 | {
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464 | return !(lhs < rhs);
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465 | }
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466 |
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467 | template<class T>
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468 | bool operator==(const shared_ptr<T>& lhs, nullptr_t) noexcept
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469 | {
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470 | return !lhs;
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471 | }
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472 |
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473 | template<class T>
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474 | bool operator==(nullptr_t, const shared_ptr<T>& rhs) noexcept
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475 | {
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476 | return !rhs;
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477 | }
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478 |
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479 | template<class T>
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480 | bool operator!=(const shared_ptr<T>& lhs, nullptr_t) noexcept
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481 | {
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482 | return (bool)lhs;
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483 | }
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484 |
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485 | template<class T>
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486 | bool operator!=(nullptr_t, const shared_ptr<T>& rhs) noexcept
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487 | {
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488 | return (bool)rhs;
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489 | }
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490 |
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491 | template<class T>
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492 | bool operator<(const shared_ptr<T>& lhs, nullptr_t) noexcept
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493 | {
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494 | return less<T*>{}(lhs.get(), nullptr);
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495 | }
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496 |
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497 | template<class T>
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498 | bool operator<(nullptr_t, const shared_ptr<T>& rhs) noexcept
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499 | {
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500 | return less<T*>{}(nullptr, rhs.get());
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501 | }
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502 |
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503 | template<class T>
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504 | bool operator>(const shared_ptr<T>& lhs, nullptr_t) noexcept
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505 | {
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506 | return nullptr < lhs;
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507 | }
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508 |
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509 | template<class T>
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510 | bool operator>(nullptr_t, const shared_ptr<T>& rhs) noexcept
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511 | {
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512 | return rhs < nullptr;
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513 | }
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514 |
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515 | template<class T>
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516 | bool operator<=(const shared_ptr<T>& lhs, nullptr_t) noexcept
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517 | {
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518 | return !(nullptr < lhs);
|
---|
519 | }
|
---|
520 |
|
---|
521 | template<class T>
|
---|
522 | bool operator<=(nullptr_t, const shared_ptr<T>& rhs) noexcept
|
---|
523 | {
|
---|
524 | return !(rhs < nullptr);
|
---|
525 | }
|
---|
526 |
|
---|
527 | template<class T>
|
---|
528 | bool operator>=(const shared_ptr<T>& lhs, nullptr_t) noexcept
|
---|
529 | {
|
---|
530 | return !(lhs < nullptr);
|
---|
531 | }
|
---|
532 |
|
---|
533 | template<class T>
|
---|
534 | bool operator>=(nullptr_t, const shared_ptr<T>& rhs) noexcept
|
---|
535 | {
|
---|
536 | return !(nullptr < rhs);
|
---|
537 | }
|
---|
538 |
|
---|
539 | /**
|
---|
540 | * 20.8.2.2.8, shared_ptr specialized algorithms:
|
---|
541 | */
|
---|
542 |
|
---|
543 | template<class T>
|
---|
544 | void swap(shared_ptr<T>& lhs, shared_ptr<T>& rhs) noexcept
|
---|
545 | {
|
---|
546 | lhs.swap(rhs);
|
---|
547 | }
|
---|
548 |
|
---|
549 | /**
|
---|
550 | * 20.8.2.2.9, shared_ptr casts:
|
---|
551 | */
|
---|
552 |
|
---|
553 | template<class T, class U>
|
---|
554 | shared_ptr<T> static_pointer_cast(const shared_ptr<U>& ptr) noexcept
|
---|
555 | {
|
---|
556 | if (!ptr)
|
---|
557 | return shared_ptr<T>{};
|
---|
558 |
|
---|
559 | return shared_ptr<T>{
|
---|
560 | ptr, static_cast<T*>(ptr.get())
|
---|
561 | };
|
---|
562 | }
|
---|
563 |
|
---|
564 | template<class T, class U>
|
---|
565 | shared_ptr<T> dynamic_pointer_cast(const shared_ptr<U>& ptr) noexcept
|
---|
566 | {
|
---|
567 | if (auto res = dynamic_cast<T*>(ptr.get()))
|
---|
568 | return shared_ptr<T>{ptr, res};
|
---|
569 | else
|
---|
570 | return shared_ptr<T>{};
|
---|
571 | }
|
---|
572 |
|
---|
573 | template<class T, class U>
|
---|
574 | shared_ptr<T> const_pointer_cast(const shared_ptr<U>& ptr) noexcept
|
---|
575 | {
|
---|
576 | if (!ptr)
|
---|
577 | return shared_ptr<T>{};
|
---|
578 |
|
---|
579 | return shared_ptr<T>{
|
---|
580 | ptr, const_cast<T*>(ptr.get())
|
---|
581 | };
|
---|
582 | }
|
---|
583 |
|
---|
584 | /**
|
---|
585 | * 20.8.2.2.10, shared_ptr get_deleter:
|
---|
586 | */
|
---|
587 |
|
---|
588 | template<class D, class T>
|
---|
589 | D* get_deleter(const shared_ptr<T>& ptr) noexcept
|
---|
590 | {
|
---|
591 | if (ptr.payload_)
|
---|
592 | return static_cast<D*>(ptr.payload_->deleter());
|
---|
593 | else
|
---|
594 | return nullptr;
|
---|
595 | }
|
---|
596 |
|
---|
597 | /**
|
---|
598 | * 20.8.2.2.11, shared_ptr I/O:
|
---|
599 | */
|
---|
600 |
|
---|
601 | template<class Char, class Traits, class T>
|
---|
602 | basic_ostream<Char, Traits>& operator<<(basic_ostream<Char, Traits>& os,
|
---|
603 | const shared_ptr<T>& ptr)
|
---|
604 | {
|
---|
605 | return os << ptr.get();
|
---|
606 | }
|
---|
607 | }
|
---|
608 |
|
---|
609 | #endif
|
---|