1 | <?php
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2 | /**
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3 | * Object Cache API
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4 | *
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5 | * @link http://codex.wordpress.org/Function_Reference/WP_Cache
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6 | *
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7 | * @package WordPress
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8 | * @subpackage Cache
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9 | */
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10 |
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11 | /**
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12 | * Adds data to the cache, if the cache key doesn't aleady exist.
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13 | *
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14 | * @since 2.0.0
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15 | * @uses $wp_object_cache Object Cache Class
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16 | * @see WP_Object_Cache::add()
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17 | *
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18 | * @param int|string $key The cache ID to use for retrieval later
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19 | * @param mixed $data The data to add to the cache store
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20 | * @param string $flag The group to add the cache to
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21 | * @param int $expire When the cache data should be expired
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22 | * @return unknown
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23 | */
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24 | function wp_cache_add($key, $data, $flag = '', $expire = 0) {
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25 | global $wp_object_cache;
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26 |
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27 | return $wp_object_cache->add($key, $data, $flag, $expire);
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28 | }
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29 |
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30 | /**
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31 | * Closes the cache.
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32 | *
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33 | * This function has ceased to do anything since WordPress 2.5. The
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34 | * functionality was removed along with the rest of the persistant cache. This
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35 | * does not mean that plugins can't implement this function when they need to
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36 | * make sure that the cache is cleaned up after WordPress no longer needs it.
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37 | *
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38 | * @since 2.0.0
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39 | *
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40 | * @return bool Always returns True
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41 | */
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42 | function wp_cache_close() {
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43 | return true;
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44 | }
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45 |
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46 | /**
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47 | * Removes the cache contents matching ID and flag.
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48 | *
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49 | * @since 2.0.0
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50 | * @uses $wp_object_cache Object Cache Class
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51 | * @see WP_Object_Cache::delete()
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52 | *
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53 | * @param int|string $id What the contents in the cache are called
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54 | * @param string $flag Where the cache contents are grouped
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55 | * @return bool True on successful removal, false on failure
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56 | */
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57 | function wp_cache_delete($id, $flag = '') {
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58 | global $wp_object_cache;
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59 |
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60 | return $wp_object_cache->delete($id, $flag);
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61 | }
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62 |
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63 | /**
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64 | * Removes all cache items.
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65 | *
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66 | * @since 2.0.0
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67 | * @uses $wp_object_cache Object Cache Class
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68 | * @see WP_Object_Cache::flush()
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69 | *
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70 | * @return bool Always returns true
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71 | */
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72 | function wp_cache_flush() {
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73 | global $wp_object_cache;
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74 |
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75 | return $wp_object_cache->flush();
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76 | }
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77 |
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78 | /**
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79 | * Retrieves the cache contents from the cache by ID and flag.
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80 | *
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81 | * @since 2.0.0
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82 | * @uses $wp_object_cache Object Cache Class
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83 | * @see WP_Object_Cache::get()
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84 | *
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85 | * @param int|string $id What the contents in the cache are called
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86 | * @param string $flag Where the cache contents are grouped
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87 | * @return bool|mixed False on failure to retrieve contents or the cache
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88 | * contents on success
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89 | */
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90 | function wp_cache_get($id, $flag = '') {
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91 | global $wp_object_cache;
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92 |
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93 | return $wp_object_cache->get($id, $flag);
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94 | }
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95 |
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96 | /**
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97 | * Sets up Object Cache Global and assigns it.
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98 | *
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99 | * @since 2.0.0
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100 | * @global WP_Object_Cache $wp_object_cache WordPress Object Cache
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101 | */
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102 | function wp_cache_init() {
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103 | $GLOBALS['wp_object_cache'] =& new WP_Object_Cache();
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104 | }
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105 |
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106 | /**
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107 | * Replaces the contents of the cache with new data.
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108 | *
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109 | * @since 2.0.0
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110 | * @uses $wp_object_cache Object Cache Class
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111 | * @see WP_Object_Cache::replace()
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112 | *
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113 | * @param int|string $id What to call the contents in the cache
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114 | * @param mixed $data The contents to store in the cache
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115 | * @param string $flag Where to group the cache contents
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116 | * @param int $expire When to expire the cache contents
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117 | * @return bool False if cache ID and group already exists, true on success
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118 | */
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119 | function wp_cache_replace($key, $data, $flag = '', $expire = 0) {
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120 | global $wp_object_cache;
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121 |
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122 | return $wp_object_cache->replace($key, $data, $flag, $expire);
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123 | }
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124 |
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125 | /**
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126 | * Saves the data to the cache.
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127 | *
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128 | * @since 2.0
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129 | * @uses $wp_object_cache Object Cache Class
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130 | * @see WP_Object_Cache::set()
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131 | *
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132 | * @param int|string $id What to call the contents in the cache
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133 | * @param mixed $data The contents to store in the cache
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134 | * @param string $flag Where to group the cache contents
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135 | * @param int $expire When to expire the cache contents
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136 | * @return bool False if cache ID and group already exists, true on success
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137 | */
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138 | function wp_cache_set($key, $data, $flag = '', $expire = 0) {
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139 | global $wp_object_cache;
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140 |
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141 | return $wp_object_cache->set($key, $data, $flag, $expire);
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142 | }
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143 |
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144 | /**
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145 | * Adds a group or set of groups to the list of global groups.
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146 | *
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147 | * @since 2.6.0
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148 | *
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149 | * @param string|array $groups A group or an array of groups to add
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150 | */
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151 | function wp_cache_add_global_groups( $groups ) {
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152 | // Default cache doesn't persist so nothing to do here.
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153 | return;
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154 | }
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155 |
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156 | /**
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157 | * Adds a group or set of groups to the list of non-persistent groups.
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158 | *
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159 | * @since 2.6.0
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160 | *
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161 | * @param string|array $groups A group or an array of groups to add
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162 | */
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163 | function wp_cache_add_non_persistent_groups( $groups ) {
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164 | // Default cache doesn't persist so nothing to do here.
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165 | return;
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166 | }
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167 |
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168 | /**
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169 | * WordPress Object Cache
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170 | *
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171 | * The WordPress Object Cache is used to save on trips to the database. The
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172 | * Object Cache stores all of the cache data to memory and makes the cache
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173 | * contents available by using a key, which is used to name and later retrieve
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174 | * the cache contents.
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175 | *
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176 | * The Object Cache can be replaced by other caching mechanisms by placing files
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177 | * in the wp-content folder which is looked at in wp-settings. If that file
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178 | * exists, then this file will not be included.
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179 | *
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180 | * @package WordPress
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181 | * @subpackage Cache
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182 | * @since 2.0
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183 | */
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184 | class WP_Object_Cache {
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185 |
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186 | /**
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187 | * Holds the cached objects
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188 | *
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189 | * @var array
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190 | * @access private
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191 | * @since 2.0.0
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192 | */
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193 | var $cache = array ();
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194 |
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195 | /**
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196 | * Cache objects that do not exist in the cache
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197 | *
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198 | * @var array
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199 | * @access private
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200 | * @since 2.0.0
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201 | */
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202 | var $non_existant_objects = array ();
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203 |
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204 | /**
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205 | * The amount of times the cache data was already stored in the cache.
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206 | *
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207 | * @since 2.5.0
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208 | * @access private
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209 | * @var int
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210 | */
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211 | var $cache_hits = 0;
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212 |
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213 | /**
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214 | * Amount of times the cache did not have the request in cache
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215 | *
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216 | * @var int
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217 | * @access public
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218 | * @since 2.0.0
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219 | */
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220 | var $cache_misses = 0;
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221 |
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222 | /**
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223 | * Adds data to the cache if it doesn't already exist.
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224 | *
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225 | * @uses WP_Object_Cache::get Checks to see if the cache already has data.
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226 | * @uses WP_Object_Cache::set Sets the data after the checking the cache
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227 | * contents existance.
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228 | *
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229 | * @since 2.0.0
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230 | *
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231 | * @param int|string $id What to call the contents in the cache
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232 | * @param mixed $data The contents to store in the cache
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233 | * @param string $group Where to group the cache contents
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234 | * @param int $expire When to expire the cache contents
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235 | * @return bool False if cache ID and group already exists, true on success
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236 | */
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237 | function add($id, $data, $group = 'default', $expire = '') {
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238 | if (empty ($group))
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239 | $group = 'default';
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240 |
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241 | if (false !== $this->get($id, $group, false))
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242 | return false;
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243 |
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244 | return $this->set($id, $data, $group, $expire);
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245 | }
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246 |
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247 | /**
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248 | * Remove the contents of the cache ID in the group
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249 | *
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250 | * If the cache ID does not exist in the group and $force parameter is set
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251 | * to false, then nothing will happen. The $force parameter is set to false
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252 | * by default.
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253 | *
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254 | * On success the group and the id will be added to the
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255 | * $non_existant_objects property in the class.
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256 | *
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257 | * @since 2.0.0
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258 | *
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259 | * @param int|string $id What the contents in the cache are called
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260 | * @param string $group Where the cache contents are grouped
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261 | * @param bool $force Optional. Whether to force the unsetting of the cache
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262 | * ID in the group
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263 | * @return bool False if the contents weren't deleted and true on success
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264 | */
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265 | function delete($id, $group = 'default', $force = false) {
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266 | if (empty ($group))
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267 | $group = 'default';
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268 |
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269 | if (!$force && false === $this->get($id, $group, false))
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270 | return false;
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271 |
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272 | unset ($this->cache[$group][$id]);
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273 | $this->non_existant_objects[$group][$id] = true;
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274 | return true;
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275 | }
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276 |
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277 | /**
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278 | * Clears the object cache of all data
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279 | *
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280 | * @since 2.0.0
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281 | *
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282 | * @return bool Always returns true
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283 | */
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284 | function flush() {
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285 | $this->cache = array ();
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286 |
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287 | return true;
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288 | }
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289 |
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290 | /**
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291 | * Retrieves the cache contents, if it exists
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292 | *
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293 | * The contents will be first attempted to be retrieved by searching by the
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294 | * ID in the cache group. If the cache is hit (success) then the contents
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295 | * are returned.
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296 | *
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297 | * On failure, the $non_existant_objects property is checked and if the
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298 | * cache group and ID exist in there the cache misses will not be
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299 | * incremented. If not in the nonexistant objects property, then the cache
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300 | * misses will be incremented and the cache group and ID will be added to
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301 | * the nonexistant objects.
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302 | *
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303 | * @since 2.0.0
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304 | *
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305 | * @param int|string $id What the contents in the cache are called
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306 | * @param string $group Where the cache contents are grouped
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307 | * @return bool|mixed False on failure to retrieve contents or the cache
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308 | * contents on success
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309 | */
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310 | function get($id, $group = 'default') {
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311 | if (empty ($group))
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312 | $group = 'default';
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313 |
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314 | if (isset ($this->cache[$group][$id])) {
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315 | $this->cache_hits += 1;
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316 | if ( is_object($this->cache[$group][$id]) )
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317 | return wp_clone($this->cache[$group][$id]);
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318 | else
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319 | return $this->cache[$group][$id];
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320 | }
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321 |
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322 | if ( isset ($this->non_existant_objects[$group][$id]) )
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323 | return false;
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324 |
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325 | $this->non_existant_objects[$group][$id] = true;
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326 | $this->cache_misses += 1;
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327 | return false;
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328 | }
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329 |
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330 | /**
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331 | * Replace the contents in the cache, if contents already exist
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332 | *
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333 | * @since 2.0.0
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334 | * @see WP_Object_Cache::set()
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335 | *
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336 | * @param int|string $id What to call the contents in the cache
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337 | * @param mixed $data The contents to store in the cache
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338 | * @param string $group Where to group the cache contents
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339 | * @param int $expire When to expire the cache contents
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340 | * @return bool False if not exists, true if contents were replaced
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341 | */
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342 | function replace($id, $data, $group = 'default', $expire = '') {
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343 | if (empty ($group))
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344 | $group = 'default';
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345 |
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346 | if (false === $this->get($id, $group, false))
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347 | return false;
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348 |
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349 | return $this->set($id, $data, $group, $expire);
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350 | }
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351 |
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352 | /**
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353 | * Sets the data contents into the cache
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354 | *
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355 | * The cache contents is grouped by the $group parameter followed by the
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356 | * $id. This allows for duplicate ids in unique groups. Therefore, naming of
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357 | * the group should be used with care and should follow normal function
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358 | * naming guidelines outside of core WordPress usage.
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359 | *
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360 | * The $expire parameter is not used, because the cache will automatically
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361 | * expire for each time a page is accessed and PHP finishes. The method is
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362 | * more for cache plugins which use files.
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363 | *
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364 | * @since 2.0.0
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365 | *
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366 | * @param int|string $id What to call the contents in the cache
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367 | * @param mixed $data The contents to store in the cache
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368 | * @param string $group Where to group the cache contents
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369 | * @param int $expire Not Used
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370 | * @return bool Always returns true
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371 | */
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372 | function set($id, $data, $group = 'default', $expire = '') {
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373 | if (empty ($group))
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374 | $group = 'default';
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375 |
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376 | if (NULL === $data)
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377 | $data = '';
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378 |
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379 | if ( is_object($data) )
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380 | $data = wp_clone($data);
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381 |
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382 | $this->cache[$group][$id] = $data;
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383 |
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384 | if(isset($this->non_existant_objects[$group][$id]))
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385 | unset ($this->non_existant_objects[$group][$id]);
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386 |
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387 | return true;
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388 | }
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389 |
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390 | /**
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391 | * Echos the stats of the caching.
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392 | *
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393 | * Gives the cache hits, and cache misses. Also prints every cached group,
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394 | * key and the data.
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395 | *
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396 | * @since 2.0.0
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397 | */
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398 | function stats() {
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399 | echo "<p>";
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400 | echo "<strong>Cache Hits:</strong> {$this->cache_hits}<br />";
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401 | echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br />";
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402 | echo "</p>";
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403 |
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404 | foreach ($this->cache as $group => $cache) {
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405 | echo "<p>";
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406 | echo "<strong>Group:</strong> $group<br />";
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407 | echo "<strong>Cache:</strong>";
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408 | echo "<pre>";
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409 | print_r($cache);
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410 | echo "</pre>";
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411 | }
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412 | }
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413 |
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414 | /**
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415 | * PHP4 constructor; Calls PHP 5 style constructor
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416 | *
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417 | * @since 2.0.0
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418 | *
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419 | * @return WP_Object_Cache
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420 | */
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421 | function WP_Object_Cache() {
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422 | return $this->__construct();
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423 | }
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424 |
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425 | /**
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426 | * Sets up object properties; PHP 5 style constructor
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427 | *
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428 | * @since 2.0.8
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429 | * @return null|WP_Object_Cache If cache is disabled, returns null.
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430 | */
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431 | function __construct() {
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432 | /**
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433 | * @todo This should be moved to the PHP4 style constructor, PHP5
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434 | * already calls __destruct()
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435 | */
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436 | register_shutdown_function(array(&$this, "__destruct"));
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437 | }
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438 |
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439 | /**
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440 | * Will save the object cache before object is completely destroyed.
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441 | *
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442 | * Called upon object destruction, which should be when PHP ends.
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443 | *
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444 | * @since 2.0.8
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445 | *
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446 | * @return bool True value. Won't be used by PHP
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447 | */
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448 | function __destruct() {
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449 | return true;
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450 | }
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451 | }
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452 | ?>
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