1 | <?php |
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2 | |||
3 | namespace MatthiasMullie\Scrapbook\Adapters; |
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4 | |||
5 | use MatthiasMullie\Scrapbook\Adapters\Collections\MemoryStore as Collection; |
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6 | use MatthiasMullie\Scrapbook\KeyValueStore; |
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7 | |||
8 | /** |
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9 | * No-storage cache: all values will be "cached" in memory, in a simple PHP |
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10 | * array. Values will only be valid for 1 request: whatever is in memory at the |
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11 | * end of the request just dies. Other requests will start from a blank slate. |
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12 | * |
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13 | * This is mainly useful for testing purposes, where this class can let you test |
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14 | * application logic against cache, without having to run a cache server. |
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15 | * |
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16 | * @author Matthias Mullie <[email protected]> |
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17 | * @copyright Copyright (c) 2014, Matthias Mullie. All rights reserved |
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18 | * @license LICENSE MIT |
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19 | */ |
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20 | class MemoryStore implements KeyValueStore |
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21 | { |
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22 | /** |
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23 | * @var array |
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24 | */ |
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25 | protected $items = array(); |
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26 | |||
27 | /** |
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28 | * @var int |
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29 | */ |
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30 | protected $limit = 0; |
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31 | |||
32 | /** |
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33 | * @var int |
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34 | */ |
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35 | protected $size = 0; |
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36 | |||
37 | /** |
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38 | * @param int|string $limit Memory limit in bytes (defaults to 10% of memory_limit) |
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39 | */ |
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40 | public function __construct($limit = null) |
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41 | { |
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42 | if (null === $limit) { |
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43 | $phpLimit = ini_get('memory_limit'); |
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44 | if ($phpLimit <= 0) { |
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45 | $this->limit = PHP_INT_MAX; |
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46 | } else { |
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47 | $this->limit = (int) ($this->shorthandToBytes($phpLimit) / 10); |
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48 | } |
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49 | } else { |
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50 | $this->limit = $this->shorthandToBytes($limit); |
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51 | } |
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52 | } |
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53 | |||
54 | /** |
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55 | * {@inheritdoc} |
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56 | */ |
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57 | public function get($key, &$token = null) |
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58 | { |
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59 | if (!$this->exists($key)) { |
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60 | $token = null; |
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61 | |||
62 | return false; |
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63 | } |
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64 | |||
65 | $value = $this->items[$key][0]; |
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66 | |||
67 | // use serialized version of stored value as CAS token |
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68 | $token = $value; |
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69 | |||
70 | return unserialize($value); |
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71 | } |
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72 | |||
73 | /** |
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74 | * {@inheritdoc} |
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75 | */ |
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76 | public function getMulti(array $keys, array &$tokens = null) |
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77 | { |
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78 | $items = array(); |
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79 | $tokens = array(); |
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80 | |||
81 | foreach ($keys as $key) { |
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82 | if (!$this->exists($key)) { |
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83 | // omit missing keys from return array |
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84 | continue; |
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85 | } |
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86 | |||
87 | $items[$key] = $this->get($key, $token); |
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88 | $tokens[$key] = $token; |
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89 | } |
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90 | |||
91 | return $items; |
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92 | } |
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93 | |||
94 | /** |
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95 | * {@inheritdoc} |
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96 | */ |
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97 | public function set($key, $value, $expire = 0) |
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98 | { |
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99 | $this->size -= isset($this->items[$key]) ? strlen($this->items[$key][0]) : 0; |
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100 | |||
101 | $value = serialize($value); |
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102 | $expire = $this->normalizeTime($expire); |
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103 | $this->items[$key] = array($value, $expire); |
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104 | |||
105 | $this->size += strlen($value); |
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106 | $this->lru($key); |
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107 | $this->evict(); |
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108 | |||
109 | return true; |
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110 | } |
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111 | |||
112 | /** |
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113 | * {@inheritdoc} |
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114 | */ |
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115 | public function setMulti(array $items, $expire = 0) |
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116 | { |
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117 | $success = array(); |
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118 | foreach ($items as $key => $value) { |
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119 | $success[$key] = $this->set($key, $value, $expire); |
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120 | } |
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121 | |||
122 | return $success; |
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123 | } |
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124 | |||
125 | /** |
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126 | * {@inheritdoc} |
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127 | */ |
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128 | public function delete($key) |
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129 | { |
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130 | $exists = $this->exists($key); |
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131 | |||
132 | if ($exists) { |
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133 | $this->size -= strlen($this->items[$key][0]); |
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134 | unset($this->items[$key]); |
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135 | } |
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136 | |||
137 | return $exists; |
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138 | } |
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139 | |||
140 | /** |
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141 | * {@inheritdoc} |
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142 | */ |
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143 | public function deleteMulti(array $keys) |
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144 | { |
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145 | $success = array(); |
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146 | |||
147 | foreach ($keys as $key) { |
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148 | $success[$key] = $this->delete($key); |
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149 | } |
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150 | |||
151 | return $success; |
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152 | } |
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153 | |||
154 | /** |
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155 | * {@inheritdoc} |
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156 | */ |
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157 | public function add($key, $value, $expire = 0) |
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158 | { |
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159 | if ($this->exists($key)) { |
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160 | return false; |
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161 | } |
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162 | |||
163 | return $this->set($key, $value, $expire); |
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164 | } |
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165 | |||
166 | /** |
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167 | * {@inheritdoc} |
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168 | */ |
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169 | public function replace($key, $value, $expire = 0) |
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170 | { |
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171 | if (!$this->exists($key)) { |
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172 | return false; |
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173 | } |
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174 | |||
175 | return $this->set($key, $value, $expire); |
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176 | } |
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177 | |||
178 | /** |
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179 | * {@inheritdoc} |
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180 | */ |
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181 | public function cas($token, $key, $value, $expire = 0) |
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182 | { |
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183 | if (!$this->exists($key)) { |
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184 | return false; |
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185 | } |
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186 | |||
187 | $this->get($key, $comparison); |
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188 | if ($comparison !== $token) { |
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189 | return false; |
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190 | } |
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191 | |||
192 | return $this->set($key, $value, $expire); |
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193 | } |
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194 | |||
195 | /** |
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196 | * {@inheritdoc} |
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197 | */ |
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198 | public function increment($key, $offset = 1, $initial = 0, $expire = 0) |
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199 | { |
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200 | if ($offset <= 0 || $initial < 0) { |
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201 | return false; |
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202 | } |
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203 | |||
204 | return $this->doIncrement($key, $offset, $initial, $expire); |
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205 | } |
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206 | |||
207 | /** |
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208 | * {@inheritdoc} |
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209 | */ |
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210 | public function decrement($key, $offset = 1, $initial = 0, $expire = 0) |
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211 | { |
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212 | if ($offset <= 0 || $initial < 0) { |
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213 | return false; |
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214 | } |
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215 | |||
216 | return $this->doIncrement($key, -$offset, $initial, $expire); |
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217 | } |
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218 | |||
219 | /** |
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220 | * {@inheritdoc} |
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221 | */ |
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222 | public function touch($key, $expire) |
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223 | { |
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224 | $expire = $this->normalizeTime($expire); |
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225 | |||
226 | // get current value & re-save it, with new expiration |
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227 | $value = $this->get($key, $token); |
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228 | |||
229 | return $this->cas($token, $key, $value, $expire); |
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230 | } |
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231 | |||
232 | /** |
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233 | * {@inheritdoc} |
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234 | */ |
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235 | public function flush() |
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236 | { |
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237 | $this->items = array(); |
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238 | $this->size = 0; |
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239 | |||
240 | return true; |
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241 | } |
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242 | |||
243 | /** |
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244 | * {@inheritdoc} |
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245 | */ |
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246 | public function getCollection($name) |
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247 | { |
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248 | return new Collection($this, $name); |
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249 | } |
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250 | |||
251 | /** |
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252 | * Checks if a value exists in cache and is not yet expired. |
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253 | * |
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254 | * @param string $key |
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255 | * |
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256 | * @return bool |
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257 | */ |
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258 | protected function exists($key) |
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259 | { |
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260 | if (!array_key_exists($key, $this->items)) { |
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261 | // key not in cache |
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262 | return false; |
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263 | } |
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264 | |||
265 | $expire = $this->items[$key][1]; |
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266 | if (0 !== $expire && $expire < time()) { |
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267 | // not permanent & already expired |
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268 | $this->size -= strlen($this->items[$key][0]); |
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269 | unset($this->items[$key]); |
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270 | |||
271 | return false; |
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272 | } |
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273 | |||
274 | $this->lru($key); |
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275 | |||
276 | return true; |
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277 | } |
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278 | |||
279 | /** |
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280 | * Shared between increment/decrement: both have mostly the same logic |
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281 | * (decrement just increments a negative value), but need their validation |
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282 | * split up (increment won't accept negative values). |
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283 | * |
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284 | * @param string $key |
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285 | * @param int $offset |
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286 | * @param int $initial |
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287 | * @param int $expire |
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288 | * |
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289 | * @return int|bool |
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290 | */ |
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291 | protected function doIncrement($key, $offset, $initial, $expire) |
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292 | { |
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293 | if (!$this->exists($key)) { |
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294 | $this->set($key, $initial, $expire); |
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295 | |||
296 | return $initial; |
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297 | } |
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298 | |||
299 | $value = $this->get($key); |
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300 | if (!is_numeric($value) || $value < 0) { |
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301 | return false; |
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302 | } |
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303 | |||
304 | $value += $offset; |
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305 | // value can never be lower than 0 |
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306 | $value = max(0, $value); |
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307 | $this->set($key, $value, $expire); |
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308 | |||
309 | return $value; |
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310 | } |
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311 | |||
312 | /** |
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313 | * Times can be: |
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314 | * * relative (in seconds) to current time, within 30 days |
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315 | * * absolute unix timestamp |
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316 | * * 0, for infinity. |
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317 | * |
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318 | * The first case (relative time) will be normalized into a fixed absolute |
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319 | * timestamp. |
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320 | * |
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321 | * @param int $time |
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322 | * |
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323 | * @return int |
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324 | */ |
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325 | protected function normalizeTime($time) |
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326 | { |
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327 | // 0 = infinity |
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328 | if (!$time) { |
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329 | return 0; |
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330 | } |
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331 | |||
332 | // relative time in seconds, <30 days |
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333 | if ($time < 30 * 24 * 60 * 60) { |
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334 | $time += time(); |
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335 | } |
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336 | |||
337 | return $time; |
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338 | } |
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339 | |||
340 | /** |
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341 | * This cache uses least recently used algorithm. This is to be called |
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342 | * with the key to be marked as just used. |
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343 | */ |
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344 | protected function lru($key) |
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345 | { |
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346 | // move key that has just been used to last position in the array |
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347 | $value = $this->items[$key]; |
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348 | unset($this->items[$key]); |
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349 | $this->items[$key] = $value; |
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350 | } |
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351 | |||
352 | /** |
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353 | * Least recently used cache values will be evicted from cache should |
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354 | * it fill up too much. |
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355 | */ |
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356 | protected function evict() |
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357 | { |
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358 | while ($this->size > $this->limit && !empty($this->items)) { |
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359 | $item = array_shift($this->items); |
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360 | $this->size -= strlen($item[0]); |
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361 | } |
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362 | } |
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363 | |||
364 | /** |
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365 | * Understands shorthand byte values (as used in e.g. memory_limit ini |
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366 | * setting) and converts them into bytes. |
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367 | * |
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368 | * @see http://php.net/manual/en/faq.using.php#faq.using.shorthandbytes |
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369 | * |
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370 | * @param string|int $shorthand Amount of bytes (int) or shorthand value (e.g. 512M) |
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371 | * |
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372 | * @return int |
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373 | */ |
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374 | protected function shorthandToBytes($shorthand) |
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375 | { |
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376 | if (is_numeric($shorthand)) { |
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377 | // make sure that when float(1.234E17) is passed in, it doesn't get |
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378 | // cast to string('1.234E17'), then to int(1) |
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379 | return $shorthand; |
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380 | } |
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381 | |||
382 | $units = array('B' => 1024, 'M' => pow(1024, 2), 'G' => pow(1024, 3)); |
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383 | |||
384 | return (int) preg_replace_callback('/^([0-9]+)('.implode('|', array_keys($units)).')$/', function ($match) use ($units) { |
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385 | return $match[1] * $units[$match[2]]; |
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386 | }, $shorthand); |
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387 | } |
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388 | } |
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389 |