Total Complexity | 48 |
Total Lines | 492 |
Duplicated Lines | 0 % |
Changes | 6 | ||
Bugs | 0 | Features | 0 |
Complex classes like SQL often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use SQL, and based on these observations, apply Extract Interface, too.
1 | <?php |
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19 | abstract class SQL implements KeyValueStore |
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20 | { |
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21 | /** |
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22 | * @var \PDO |
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23 | */ |
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24 | protected $client; |
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25 | |||
26 | /** |
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27 | * @var string |
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28 | */ |
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29 | protected $table; |
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30 | |||
31 | /** |
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32 | * Create the database/indices if it does not already exist. |
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33 | */ |
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34 | abstract protected function init(); |
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35 | |||
36 | /** |
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37 | * @param string $table |
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38 | */ |
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39 | public function __construct(\PDO $client, $table = 'cache') |
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40 | { |
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41 | $this->client = $client; |
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42 | $this->table = $table; |
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43 | |||
44 | // don't throw exceptions - it's ok to fail, as long as the return value |
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45 | // reflects that! |
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46 | $this->client->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_SILENT); |
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47 | |||
48 | // make sure the database exists (or just "fail" silently) |
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49 | $this->init(); |
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50 | |||
51 | // now's a great time to clean up all expired items |
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52 | $this->clearExpired(); |
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53 | } |
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54 | |||
55 | /** |
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56 | * {@inheritdoc} |
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57 | */ |
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58 | public function get($key, &$token = null) |
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59 | { |
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60 | $statement = $this->client->prepare( |
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61 | "SELECT v |
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62 | FROM $this->table |
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63 | WHERE k = :key AND (e IS NULL OR e > :expire)" |
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64 | ); |
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65 | $statement->execute(array( |
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66 | ':key' => $key, |
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67 | ':expire' => date('Y-m-d H:i:s'), // right now! |
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68 | )); |
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69 | |||
70 | $result = $statement->fetch(\PDO::FETCH_ASSOC); |
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71 | |||
72 | if (!isset($result['v'])) { |
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73 | $token = null; |
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74 | |||
75 | return false; |
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76 | } |
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77 | |||
78 | $token = $result['v']; |
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79 | |||
80 | return $this->unserialize($result['v']); |
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81 | } |
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82 | |||
83 | /** |
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84 | * {@inheritdoc} |
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85 | */ |
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86 | public function getMulti(array $keys, array &$tokens = null) |
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87 | { |
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88 | $tokens = array(); |
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89 | if (empty($keys)) { |
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90 | return array(); |
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91 | } |
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92 | |||
93 | // escape input, can't bind multiple params for IN() |
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94 | $quoted = array(); |
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95 | foreach ($keys as $key) { |
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96 | $quoted[] = $this->client->quote($key); |
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97 | } |
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98 | |||
99 | $statement = $this->client->prepare( |
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100 | "SELECT k, v |
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101 | FROM $this->table |
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102 | WHERE |
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103 | k IN (".implode(',', $quoted).') AND |
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104 | (e IS NULL OR e > :expire)' |
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105 | ); |
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106 | $statement->execute(array(':expire' => date('Y-m-d H:i:s'))); |
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107 | $values = $statement->fetchAll(\PDO::FETCH_ASSOC); |
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108 | |||
109 | $result = array(); |
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110 | $tokens = array(); |
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111 | foreach ($values as $value) { |
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112 | $tokens[$value['k']] = $value['v']; |
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113 | $result[$value['k']] = $this->unserialize($value['v']); |
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114 | } |
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115 | |||
116 | return $result; |
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117 | } |
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118 | |||
119 | /** |
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120 | * {@inheritdoc} |
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121 | */ |
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122 | public function set($key, $value, $expire = 0) |
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123 | { |
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124 | // PostgreSQL doesn't have a decent UPSERT (like REPLACE or even INSERT |
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125 | // ... ON DUPLICATE KEY UPDATE ...); here's a "works for all" downgrade |
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126 | $success = $this->add($key, $value, $expire); |
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127 | if ($success) { |
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128 | return true; |
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129 | } |
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130 | |||
131 | $success = $this->replace($key, $value, $expire); |
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132 | if ($success) { |
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133 | return true; |
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134 | } |
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135 | |||
136 | return false; |
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137 | } |
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138 | |||
139 | /** |
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140 | * {@inheritdoc} |
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141 | */ |
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142 | public function setMulti(array $items, $expire = 0) |
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143 | { |
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144 | $success = array(); |
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145 | |||
146 | // PostgreSQL's lack of a decent UPSERT is even worse for multiple |
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147 | // values - we can only do them one at a time... |
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148 | foreach ($items as $key => $value) { |
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149 | $success[$key] = $this->set($key, $value, $expire); |
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150 | } |
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151 | |||
152 | return $success; |
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153 | } |
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154 | |||
155 | /** |
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156 | * {@inheritdoc} |
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157 | */ |
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158 | public function delete($key) |
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159 | { |
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160 | $statement = $this->client->prepare( |
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161 | "DELETE FROM $this->table |
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162 | WHERE k = :key" |
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163 | ); |
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164 | |||
165 | $statement->execute(array(':key' => $key)); |
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166 | |||
167 | return 1 === $statement->rowCount(); |
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168 | } |
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169 | |||
170 | /** |
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171 | * {@inheritdoc} |
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172 | */ |
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173 | public function deleteMulti(array $keys) |
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174 | { |
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175 | if (empty($keys)) { |
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176 | return array(); |
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177 | } |
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178 | |||
179 | // we'll need these to figure out which could not be deleted... |
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180 | $items = $this->getMulti($keys); |
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181 | |||
182 | // escape input, can't bind multiple params for IN() |
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183 | $quoted = array(); |
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184 | foreach ($keys as $key) { |
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185 | $quoted[] = $this->client->quote($key); |
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186 | } |
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187 | |||
188 | $statement = $this->client->query( |
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189 | "DELETE FROM $this->table |
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190 | WHERE k IN (".implode(',', $quoted).')' |
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191 | ); |
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192 | |||
193 | /* |
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194 | * In case of connection problems, we may not have been able to delete |
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195 | * any. Otherwise, we'll use the getMulti() results to figure out which |
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196 | * couldn't be deleted because they didn't exist at that time. |
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197 | */ |
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198 | $success = 0 !== $statement->rowCount(); |
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199 | $success = array_fill_keys($keys, $success); |
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200 | foreach ($keys as $key) { |
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201 | if (!array_key_exists($key, $items)) { |
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202 | $success[$key] = false; |
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203 | } |
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204 | } |
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205 | |||
206 | return $success; |
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207 | } |
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208 | |||
209 | /** |
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210 | * {@inheritdoc} |
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211 | */ |
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212 | public function add($key, $value, $expire = 0) |
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213 | { |
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214 | $value = $this->serialize($value); |
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215 | $expire = $this->expire($expire); |
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216 | |||
217 | $this->clearExpired(); |
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218 | |||
219 | $statement = $this->client->prepare( |
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220 | "INSERT INTO $this->table (k, v, e) |
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221 | VALUES (:key, :value, :expire)" |
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222 | ); |
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223 | |||
224 | $statement->execute(array( |
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225 | ':key' => $key, |
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226 | ':value' => $value, |
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227 | ':expire' => $expire, |
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228 | )); |
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229 | |||
230 | return 1 === $statement->rowCount(); |
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231 | } |
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232 | |||
233 | /** |
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234 | * {@inheritdoc} |
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235 | */ |
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236 | public function replace($key, $value, $expire = 0) |
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237 | { |
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238 | $value = $this->serialize($value); |
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239 | $expire = $this->expire($expire); |
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240 | |||
241 | $this->clearExpired(); |
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242 | |||
243 | $statement = $this->client->prepare( |
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244 | "UPDATE $this->table |
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245 | SET v = :value, e = :expire |
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246 | WHERE k = :key" |
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247 | ); |
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248 | |||
249 | $statement->execute(array( |
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250 | ':key' => $key, |
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251 | ':value' => $value, |
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252 | ':expire' => $expire, |
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253 | )); |
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254 | |||
255 | if (1 === $statement->rowCount()) { |
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256 | return true; |
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257 | } |
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258 | |||
259 | // if the value we've just replaced was the same as the replacement, as |
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260 | // well as the same expiration time, rowCount will have been 0, but the |
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261 | // operation was still a success |
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262 | $statement = $this->client->prepare( |
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263 | "SELECT e |
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264 | FROM $this->table |
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265 | WHERE k = :key AND v = :value" |
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266 | ); |
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267 | $statement->execute(array( |
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268 | ':key' => $key, |
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269 | ':value' => $value, |
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270 | )); |
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271 | |||
272 | return $statement->fetchColumn(0) === $expire; |
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273 | } |
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274 | |||
275 | /** |
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276 | * {@inheritdoc} |
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277 | */ |
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278 | public function cas($token, $key, $value, $expire = 0) |
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279 | { |
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280 | $value = $this->serialize($value); |
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281 | $expire = $this->expire($expire); |
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282 | |||
283 | $this->clearExpired(); |
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284 | |||
285 | $statement = $this->client->prepare( |
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286 | "UPDATE $this->table |
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287 | SET v = :value, e = :expire |
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288 | WHERE k = :key AND v = :token" |
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289 | ); |
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290 | |||
291 | $statement->execute(array( |
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292 | ':key' => $key, |
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293 | ':value' => $value, |
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294 | ':expire' => $expire, |
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295 | ':token' => $token, |
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296 | )); |
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297 | |||
298 | if (1 === $statement->rowCount()) { |
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299 | return true; |
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300 | } |
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301 | |||
302 | // if the value we've just cas'ed was the same as the replacement, as |
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303 | // well as the same expiration time, rowCount will have been 0, but the |
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304 | // operation was still a success |
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305 | $statement = $this->client->prepare( |
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306 | "SELECT e |
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307 | FROM $this->table |
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308 | WHERE k = :key AND v = :value AND v = :token" |
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309 | ); |
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310 | $statement->execute(array( |
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311 | ':key' => $key, |
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312 | ':value' => $value, |
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313 | ':token' => $token, |
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314 | )); |
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315 | |||
316 | return $statement->fetchColumn(0) === $expire; |
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317 | } |
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318 | |||
319 | /** |
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320 | * {@inheritdoc} |
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321 | */ |
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322 | public function increment($key, $offset = 1, $initial = 0, $expire = 0) |
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323 | { |
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324 | if ($offset <= 0 || $initial < 0) { |
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325 | return false; |
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326 | } |
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327 | |||
328 | return $this->doIncrement($key, $offset, $initial, $expire); |
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329 | } |
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330 | |||
331 | /** |
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332 | * {@inheritdoc} |
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333 | */ |
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334 | public function decrement($key, $offset = 1, $initial = 0, $expire = 0) |
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335 | { |
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336 | if ($offset <= 0 || $initial < 0) { |
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337 | return false; |
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338 | } |
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339 | |||
340 | return $this->doIncrement($key, -$offset, $initial, $expire); |
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341 | } |
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342 | |||
343 | /** |
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344 | * {@inheritdoc} |
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345 | */ |
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346 | public function touch($key, $expire) |
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347 | { |
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348 | $expire = $this->expire($expire); |
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349 | |||
350 | $this->clearExpired(); |
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351 | |||
352 | $statement = $this->client->prepare( |
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353 | "UPDATE $this->table |
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354 | SET e = :expire |
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355 | WHERE k = :key" |
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356 | ); |
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357 | |||
358 | $statement->execute(array( |
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359 | ':key' => $key, |
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360 | ':expire' => $expire, |
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361 | )); |
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362 | |||
363 | return 1 === $statement->rowCount(); |
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364 | } |
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365 | |||
366 | /** |
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367 | * {@inheritdoc} |
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368 | */ |
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369 | public function flush() |
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370 | { |
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371 | // TRUNCATE doesn't work on SQLite - DELETE works for all |
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372 | return false !== $this->client->exec("DELETE FROM $this->table"); |
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373 | } |
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374 | |||
375 | /** |
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376 | * {@inheritdoc} |
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377 | */ |
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378 | public function getCollection($name) |
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381 | } |
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382 | |||
383 | /** |
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384 | * Shared between increment/decrement: both have mostly the same logic |
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385 | * (decrement just increments a negative value), but need their validation |
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386 | * & use of non-ttl native methods split up. |
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387 | * |
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388 | * @param string $key |
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389 | * @param int $offset |
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390 | * @param int $initial |
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391 | * @param int $expire |
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392 | * |
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393 | * @return int|bool |
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394 | */ |
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395 | protected function doIncrement($key, $offset, $initial, $expire) |
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431 | } |
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432 | |||
433 | /** |
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434 | * Expired entries shouldn't keep filling up the database. Additionally, |
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435 | * we will want to remove those in order to properly rely on INSERT (for |
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436 | * add) and UPDATE (for replace), which assume a column exists or not, not |
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437 | * taking the expiration status into consideration. |
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438 | * An expired column should simply not exist. |
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439 | */ |
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440 | protected function clearExpired() |
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441 | { |
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442 | $statement = $this->client->prepare( |
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443 | "DELETE FROM $this->table |
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444 | WHERE e < :expire" |
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445 | ); |
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446 | |||
447 | $statement->execute(array(':expire' => date('Y-m-d H:i:s'))); |
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448 | } |
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449 | |||
450 | /** |
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451 | * Transforms expiration times into TIMESTAMP (Y-m-d H:i:s) format, which DB |
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452 | * will understand and be able to compare with other dates. |
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453 | * |
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454 | * @param int $expire |
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455 | * |
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456 | * @return string|null |
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457 | */ |
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458 | protected function expire($expire) |
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459 | { |
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460 | if (0 === $expire) { |
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461 | return; |
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462 | } |
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463 | |||
464 | // relative time in seconds, <30 days |
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465 | if ($expire < 30 * 24 * 60 * 60) { |
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466 | $expire += time(); |
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467 | } |
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468 | |||
469 | return date('Y-m-d H:i:s', $expire); |
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470 | } |
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471 | |||
472 | /** |
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473 | * I originally didn't want to serialize numeric values because I planned |
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474 | * on incrementing them in the DB, but revisited that idea. |
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475 | * However, not serializing numbers still causes some small DB storage gains |
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476 | * and it's safe (serialized data can never be confused for an int). |
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477 | * |
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478 | * @param mixed $value |
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479 | * |
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480 | * @return string|int |
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481 | */ |
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482 | protected function serialize($value) |
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485 | } |
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486 | |||
487 | /** |
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488 | * Numbers aren't serialized for storage size purposes. |
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489 | * |
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490 | * @param mixed $value |
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491 | * |
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492 | * @return mixed|int|float |
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493 | */ |
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494 | protected function unserialize($value) |
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495 | { |
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496 | if (is_numeric($value)) { |
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511 | } |
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512 | } |
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513 |