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1 <?php |
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2 /** |
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3 * Object Cache API: WP_Object_Cache class |
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4 * |
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5 * @package WordPress |
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6 * @subpackage Cache |
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7 * @since 5.4.0 |
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8 */ |
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9 |
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10 /** |
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11 * Core class that implements an object cache. |
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12 * |
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13 * The WordPress Object Cache is used to save on trips to the database. The |
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14 * Object Cache stores all of the cache data to memory and makes the cache |
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15 * contents available by using a key, which is used to name and later retrieve |
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16 * the cache contents. |
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17 * |
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18 * The Object Cache can be replaced by other caching mechanisms by placing files |
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19 * in the wp-content folder which is looked at in wp-settings. If that file |
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20 * exists, then this file will not be included. |
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21 * |
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22 * @since 2.0.0 |
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23 */ |
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24 class WP_Object_Cache { |
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25 |
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26 /** |
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27 * Holds the cached objects. |
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28 * |
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29 * @since 2.0.0 |
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30 * @var array |
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31 */ |
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32 private $cache = array(); |
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33 |
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34 /** |
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35 * The amount of times the cache data was already stored in the cache. |
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36 * |
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37 * @since 2.5.0 |
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38 * @var int |
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39 */ |
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40 public $cache_hits = 0; |
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41 |
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42 /** |
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43 * Amount of times the cache did not have the request in cache. |
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44 * |
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45 * @since 2.0.0 |
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46 * @var int |
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47 */ |
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48 public $cache_misses = 0; |
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49 |
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50 /** |
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51 * List of global cache groups. |
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52 * |
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53 * @since 3.0.0 |
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54 * @var array |
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55 */ |
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56 protected $global_groups = array(); |
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57 |
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58 /** |
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59 * The blog prefix to prepend to keys in non-global groups. |
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60 * |
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61 * @since 3.5.0 |
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62 * @var string |
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63 */ |
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64 private $blog_prefix; |
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65 |
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66 /** |
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67 * Holds the value of is_multisite(). |
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68 * |
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69 * @since 3.5.0 |
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70 * @var bool |
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71 */ |
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72 private $multisite; |
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73 |
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74 /** |
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75 * Sets up object properties; PHP 5 style constructor. |
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76 * |
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77 * @since 2.0.8 |
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78 */ |
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79 public function __construct() { |
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80 $this->multisite = is_multisite(); |
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81 $this->blog_prefix = $this->multisite ? get_current_blog_id() . ':' : ''; |
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82 } |
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83 |
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84 /** |
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85 * Makes private properties readable for backward compatibility. |
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86 * |
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87 * @since 4.0.0 |
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88 * |
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89 * @param string $name Property to get. |
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90 * @return mixed Property. |
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91 */ |
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92 public function __get( $name ) { |
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93 return $this->$name; |
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94 } |
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95 |
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96 /** |
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97 * Makes private properties settable for backward compatibility. |
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98 * |
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99 * @since 4.0.0 |
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100 * |
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101 * @param string $name Property to set. |
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102 * @param mixed $value Property value. |
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103 * @return mixed Newly-set property. |
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104 */ |
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105 public function __set( $name, $value ) { |
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106 return $this->$name = $value; |
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107 } |
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108 |
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109 /** |
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110 * Makes private properties checkable for backward compatibility. |
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111 * |
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112 * @since 4.0.0 |
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113 * |
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114 * @param string $name Property to check if set. |
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115 * @return bool Whether the property is set. |
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116 */ |
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117 public function __isset( $name ) { |
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118 return isset( $this->$name ); |
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119 } |
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120 |
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121 /** |
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122 * Makes private properties un-settable for backward compatibility. |
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123 * |
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124 * @since 4.0.0 |
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125 * |
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126 * @param string $name Property to unset. |
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127 */ |
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128 public function __unset( $name ) { |
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129 unset( $this->$name ); |
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130 } |
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131 |
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132 /** |
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133 * Adds data to the cache if it doesn't already exist. |
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134 * |
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135 * @since 2.0.0 |
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136 * |
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137 * @uses WP_Object_Cache::_exists() Checks to see if the cache already has data. |
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138 * @uses WP_Object_Cache::set() Sets the data after the checking the cache |
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139 * contents existence. |
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140 * |
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141 * @param int|string $key What to call the contents in the cache. |
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142 * @param mixed $data The contents to store in the cache. |
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143 * @param string $group Optional. Where to group the cache contents. Default 'default'. |
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144 * @param int $expire Optional. When to expire the cache contents. Default 0 (no expiration). |
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145 * @return bool True on success, false if cache key and group already exist. |
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146 */ |
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147 public function add( $key, $data, $group = 'default', $expire = 0 ) { |
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148 if ( wp_suspend_cache_addition() ) { |
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149 return false; |
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150 } |
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151 |
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152 if ( empty( $group ) ) { |
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153 $group = 'default'; |
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154 } |
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155 |
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156 $id = $key; |
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157 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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158 $id = $this->blog_prefix . $key; |
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159 } |
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160 |
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161 if ( $this->_exists( $id, $group ) ) { |
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162 return false; |
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163 } |
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164 |
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165 return $this->set( $key, $data, $group, (int) $expire ); |
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166 } |
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167 |
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168 /** |
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169 * Sets the list of global cache groups. |
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170 * |
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171 * @since 3.0.0 |
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172 * |
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173 * @param array $groups List of groups that are global. |
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174 */ |
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175 public function add_global_groups( $groups ) { |
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176 $groups = (array) $groups; |
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177 |
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178 $groups = array_fill_keys( $groups, true ); |
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179 $this->global_groups = array_merge( $this->global_groups, $groups ); |
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180 } |
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181 |
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182 /** |
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183 * Decrements numeric cache item's value. |
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184 * |
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185 * @since 3.3.0 |
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186 * |
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187 * @param int|string $key The cache key to decrement. |
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188 * @param int $offset Optional. The amount by which to decrement the item's value. Default 1. |
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189 * @param string $group Optional. The group the key is in. Default 'default'. |
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190 * @return int|false The item's new value on success, false on failure. |
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191 */ |
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192 public function decr( $key, $offset = 1, $group = 'default' ) { |
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193 if ( empty( $group ) ) { |
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194 $group = 'default'; |
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195 } |
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196 |
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197 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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198 $key = $this->blog_prefix . $key; |
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199 } |
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200 |
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201 if ( ! $this->_exists( $key, $group ) ) { |
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202 return false; |
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203 } |
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204 |
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205 if ( ! is_numeric( $this->cache[ $group ][ $key ] ) ) { |
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206 $this->cache[ $group ][ $key ] = 0; |
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207 } |
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208 |
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209 $offset = (int) $offset; |
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210 |
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211 $this->cache[ $group ][ $key ] -= $offset; |
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212 |
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213 if ( $this->cache[ $group ][ $key ] < 0 ) { |
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214 $this->cache[ $group ][ $key ] = 0; |
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215 } |
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216 |
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217 return $this->cache[ $group ][ $key ]; |
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218 } |
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219 |
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220 /** |
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221 * Removes the contents of the cache key in the group. |
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222 * |
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223 * If the cache key does not exist in the group, then nothing will happen. |
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224 * |
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225 * @since 2.0.0 |
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226 * |
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227 * @param int|string $key What the contents in the cache are called. |
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228 * @param string $group Optional. Where the cache contents are grouped. Default 'default'. |
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229 * @param bool $deprecated Optional. Unused. Default false. |
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230 * @return bool False if the contents weren't deleted and true on success. |
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231 */ |
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232 public function delete( $key, $group = 'default', $deprecated = false ) { |
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233 if ( empty( $group ) ) { |
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234 $group = 'default'; |
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235 } |
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236 |
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237 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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238 $key = $this->blog_prefix . $key; |
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239 } |
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240 |
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241 if ( ! $this->_exists( $key, $group ) ) { |
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242 return false; |
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243 } |
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244 |
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245 unset( $this->cache[ $group ][ $key ] ); |
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246 return true; |
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247 } |
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248 |
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249 /** |
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250 * Clears the object cache of all data. |
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251 * |
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252 * @since 2.0.0 |
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253 * |
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254 * @return true Always returns true. |
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255 */ |
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256 public function flush() { |
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257 $this->cache = array(); |
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258 |
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259 return true; |
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260 } |
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261 |
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262 /** |
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263 * Retrieves the cache contents, if it exists. |
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264 * |
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265 * The contents will be first attempted to be retrieved by searching by the |
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266 * key in the cache group. If the cache is hit (success) then the contents |
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267 * are returned. |
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268 * |
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269 * On failure, the number of cache misses will be incremented. |
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270 * |
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271 * @since 2.0.0 |
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272 * |
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273 * @param int|string $key The key under which the cache contents are stored. |
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274 * @param string $group Optional. Where the cache contents are grouped. Default 'default'. |
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275 * @param bool $force Optional. Unused. Whether to force an update of the local cache |
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276 * from the persistent cache. Default false. |
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277 * @param bool $found Optional. Whether the key was found in the cache (passed by reference). |
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278 * Disambiguates a return of false, a storable value. Default null. |
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279 * @return mixed|false The cache contents on success, false on failure to retrieve contents. |
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280 */ |
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281 public function get( $key, $group = 'default', $force = false, &$found = null ) { |
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282 if ( empty( $group ) ) { |
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283 $group = 'default'; |
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284 } |
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285 |
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286 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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287 $key = $this->blog_prefix . $key; |
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288 } |
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289 |
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290 if ( $this->_exists( $key, $group ) ) { |
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291 $found = true; |
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292 $this->cache_hits += 1; |
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293 if ( is_object( $this->cache[ $group ][ $key ] ) ) { |
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294 return clone $this->cache[ $group ][ $key ]; |
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295 } else { |
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296 return $this->cache[ $group ][ $key ]; |
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297 } |
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298 } |
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299 |
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300 $found = false; |
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301 $this->cache_misses += 1; |
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302 return false; |
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303 } |
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304 |
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305 /** |
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306 * Retrieves multiple values from the cache in one call. |
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307 * |
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308 * @since 5.5.0 |
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309 * |
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310 * @param array $keys Array of keys under which the cache contents are stored. |
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311 * @param string $group Optional. Where the cache contents are grouped. Default 'default'. |
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312 * @param bool $force Optional. Whether to force an update of the local cache |
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313 * from the persistent cache. Default false. |
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314 * @return array Array of values organized into groups. |
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315 */ |
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316 public function get_multiple( $keys, $group = 'default', $force = false ) { |
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317 $values = array(); |
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318 |
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319 foreach ( $keys as $key ) { |
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320 $values[ $key ] = $this->get( $key, $group, $force ); |
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321 } |
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322 |
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323 return $values; |
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324 } |
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325 |
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326 /** |
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327 * Increments numeric cache item's value. |
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328 * |
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329 * @since 3.3.0 |
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330 * |
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331 * @param int|string $key The cache key to increment |
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332 * @param int $offset Optional. The amount by which to increment the item's value. Default 1. |
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333 * @param string $group Optional. The group the key is in. Default 'default'. |
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334 * @return int|false The item's new value on success, false on failure. |
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335 */ |
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336 public function incr( $key, $offset = 1, $group = 'default' ) { |
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337 if ( empty( $group ) ) { |
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338 $group = 'default'; |
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339 } |
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340 |
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341 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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342 $key = $this->blog_prefix . $key; |
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343 } |
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344 |
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345 if ( ! $this->_exists( $key, $group ) ) { |
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346 return false; |
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347 } |
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348 |
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349 if ( ! is_numeric( $this->cache[ $group ][ $key ] ) ) { |
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350 $this->cache[ $group ][ $key ] = 0; |
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351 } |
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352 |
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353 $offset = (int) $offset; |
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354 |
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355 $this->cache[ $group ][ $key ] += $offset; |
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356 |
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357 if ( $this->cache[ $group ][ $key ] < 0 ) { |
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358 $this->cache[ $group ][ $key ] = 0; |
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359 } |
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360 |
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361 return $this->cache[ $group ][ $key ]; |
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362 } |
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363 |
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364 /** |
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365 * Replaces the contents in the cache, if contents already exist. |
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366 * |
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367 * @since 2.0.0 |
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368 * |
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369 * @see WP_Object_Cache::set() |
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370 * |
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371 * @param int|string $key What to call the contents in the cache. |
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372 * @param mixed $data The contents to store in the cache. |
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373 * @param string $group Optional. Where to group the cache contents. Default 'default'. |
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374 * @param int $expire Optional. When to expire the cache contents. Default 0 (no expiration). |
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375 * @return bool False if not exists, true if contents were replaced. |
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376 */ |
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377 public function replace( $key, $data, $group = 'default', $expire = 0 ) { |
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378 if ( empty( $group ) ) { |
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379 $group = 'default'; |
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380 } |
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381 |
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382 $id = $key; |
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383 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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384 $id = $this->blog_prefix . $key; |
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385 } |
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386 |
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387 if ( ! $this->_exists( $id, $group ) ) { |
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388 return false; |
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389 } |
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390 |
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391 return $this->set( $key, $data, $group, (int) $expire ); |
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392 } |
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393 |
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394 /** |
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395 * Resets cache keys. |
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396 * |
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397 * @since 3.0.0 |
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398 * |
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399 * @deprecated 3.5.0 Use switch_to_blog() |
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400 * @see switch_to_blog() |
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401 */ |
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402 public function reset() { |
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403 _deprecated_function( __FUNCTION__, '3.5.0', 'switch_to_blog()' ); |
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404 |
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405 // Clear out non-global caches since the blog ID has changed. |
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406 foreach ( array_keys( $this->cache ) as $group ) { |
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407 if ( ! isset( $this->global_groups[ $group ] ) ) { |
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408 unset( $this->cache[ $group ] ); |
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409 } |
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410 } |
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411 } |
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412 |
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413 /** |
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414 * Sets the data contents into the cache. |
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415 * |
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416 * The cache contents are grouped by the $group parameter followed by the |
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417 * $key. This allows for duplicate IDs in unique groups. Therefore, naming of |
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418 * the group should be used with care and should follow normal function |
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419 * naming guidelines outside of core WordPress usage. |
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420 * |
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421 * The $expire parameter is not used, because the cache will automatically |
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422 * expire for each time a page is accessed and PHP finishes. The method is |
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423 * more for cache plugins which use files. |
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424 * |
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425 * @since 2.0.0 |
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426 * |
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427 * @param int|string $key What to call the contents in the cache. |
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428 * @param mixed $data The contents to store in the cache. |
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429 * @param string $group Optional. Where to group the cache contents. Default 'default'. |
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430 * @param int $expire Not Used. |
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431 * @return true Always returns true. |
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432 */ |
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433 public function set( $key, $data, $group = 'default', $expire = 0 ) { |
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434 if ( empty( $group ) ) { |
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435 $group = 'default'; |
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436 } |
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437 |
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438 if ( $this->multisite && ! isset( $this->global_groups[ $group ] ) ) { |
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439 $key = $this->blog_prefix . $key; |
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440 } |
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441 |
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442 if ( is_object( $data ) ) { |
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443 $data = clone $data; |
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444 } |
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445 |
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446 $this->cache[ $group ][ $key ] = $data; |
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447 return true; |
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448 } |
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449 |
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450 /** |
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451 * Echoes the stats of the caching. |
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452 * |
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453 * Gives the cache hits, and cache misses. Also prints every cached group, |
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454 * key and the data. |
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455 * |
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456 * @since 2.0.0 |
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457 */ |
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458 public function stats() { |
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459 echo '<p>'; |
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460 echo "<strong>Cache Hits:</strong> {$this->cache_hits}<br />"; |
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461 echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br />"; |
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462 echo '</p>'; |
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463 echo '<ul>'; |
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464 foreach ( $this->cache as $group => $cache ) { |
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465 echo '<li><strong>Group:</strong> ' . esc_html( $group ) . ' - ( ' . number_format( strlen( serialize( $cache ) ) / KB_IN_BYTES, 2 ) . 'k )</li>'; |
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466 } |
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467 echo '</ul>'; |
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468 } |
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469 |
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470 /** |
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471 * Switches the internal blog ID. |
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472 * |
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473 * This changes the blog ID used to create keys in blog specific groups. |
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474 * |
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475 * @since 3.5.0 |
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476 * |
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477 * @param int $blog_id Blog ID. |
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478 */ |
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479 public function switch_to_blog( $blog_id ) { |
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480 $blog_id = (int) $blog_id; |
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481 $this->blog_prefix = $this->multisite ? $blog_id . ':' : ''; |
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482 } |
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483 |
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484 /** |
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485 * Serves as a utility function to determine whether a key exists in the cache. |
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486 * |
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487 * @since 3.4.0 |
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488 * |
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489 * @param int|string $key Cache key to check for existence. |
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490 * @param string $group Cache group for the key existence check. |
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491 * @return bool Whether the key exists in the cache for the given group. |
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492 */ |
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493 protected function _exists( $key, $group ) { |
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494 return isset( $this->cache[ $group ] ) && ( isset( $this->cache[ $group ][ $key ] ) || array_key_exists( $key, $this->cache[ $group ] ) ); |
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495 } |
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496 } |