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115 office 1 <?php
2 /*
3 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
4 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
5 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
6 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
7 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
8 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
9 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
10 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
11 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
12 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
13 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
14 *
15 * This software consists of voluntary contributions made by many individuals
16 * and is licensed under the MIT license. For more information, see
17 * <http://www.doctrine-project.org>.
18 */
19  
20 namespace Doctrine\Common\Cache;
21  
22 use Riak\Bucket;
23 use Riak\Connection;
24 use Riak\Input;
25 use Riak\Exception;
26 use Riak\Object;
27  
28 /**
29 * Riak cache provider.
30 *
31 * @link www.doctrine-project.org
32 * @since 1.1
33 * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
34 */
35 class RiakCache extends CacheProvider
36 {
37 const EXPIRES_HEADER = 'X-Riak-Meta-Expires';
38  
39 /**
40 * @var \Riak\Bucket
41 */
42 private $bucket;
43  
44 /**
45 * Sets the riak bucket instance to use.
46 *
47 * @param \Riak\Bucket $bucket
48 */
49 public function __construct(Bucket $bucket)
50 {
51 $this->bucket = $bucket;
52 }
53  
54 /**
55 * {@inheritdoc}
56 */
57 protected function doFetch($id)
58 {
59 try {
60 $response = $this->bucket->get($id);
61  
62 // No objects found
63 if ( ! $response->hasObject()) {
64 return false;
65 }
66  
67 // Check for attempted siblings
68 $object = ($response->hasSiblings())
69 ? $this->resolveConflict($id, $response->getVClock(), $response->getObjectList())
70 : $response->getFirstObject();
71  
72 // Check for expired object
73 if ($this->isExpired($object)) {
74 $this->bucket->delete($object);
75  
76 return false;
77 }
78  
79 return unserialize($object->getContent());
80 } catch (Exception\RiakException $e) {
81 // Covers:
82 // - Riak\ConnectionException
83 // - Riak\CommunicationException
84 // - Riak\UnexpectedResponseException
85 // - Riak\NotFoundException
86 }
87  
88 return false;
89 }
90  
91 /**
92 * {@inheritdoc}
93 */
94 protected function doContains($id)
95 {
96 try {
97 // We only need the HEAD, not the entire object
98 $input = new Input\GetInput();
99  
100 $input->setReturnHead(true);
101  
102 $response = $this->bucket->get($id, $input);
103  
104 // No objects found
105 if ( ! $response->hasObject()) {
106 return false;
107 }
108  
109 $object = $response->getFirstObject();
110  
111 // Check for expired object
112 if ($this->isExpired($object)) {
113 $this->bucket->delete($object);
114  
115 return false;
116 }
117  
118 return true;
119 } catch (Exception\RiakException $e) {
120 // Do nothing
121 }
122  
123 return false;
124 }
125  
126 /**
127 * {@inheritdoc}
128 */
129 protected function doSave($id, $data, $lifeTime = 0)
130 {
131 try {
132 $object = new Object($id);
133  
134 $object->setContent(serialize($data));
135  
136 if ($lifeTime > 0) {
137 $object->addMetadata(self::EXPIRES_HEADER, (string) (time() + $lifeTime));
138 }
139  
140 $this->bucket->put($object);
141  
142 return true;
143 } catch (Exception\RiakException $e) {
144 // Do nothing
145 }
146  
147 return false;
148 }
149  
150 /**
151 * {@inheritdoc}
152 */
153 protected function doDelete($id)
154 {
155 try {
156 $this->bucket->delete($id);
157  
158 return true;
159 } catch (Exception\BadArgumentsException $e) {
160 // Key did not exist on cluster already
161 } catch (Exception\RiakException $e) {
162 // Covers:
163 // - Riak\Exception\ConnectionException
164 // - Riak\Exception\CommunicationException
165 // - Riak\Exception\UnexpectedResponseException
166 }
167  
168 return false;
169 }
170  
171 /**
172 * {@inheritdoc}
173 */
174 protected function doFlush()
175 {
176 try {
177 $keyList = $this->bucket->getKeyList();
178  
179 foreach ($keyList as $key) {
180 $this->bucket->delete($key);
181 }
182  
183 return true;
184 } catch (Exception\RiakException $e) {
185 // Do nothing
186 }
187  
188 return false;
189 }
190  
191 /**
192 * {@inheritdoc}
193 */
194 protected function doGetStats()
195 {
196 // Only exposed through HTTP stats API, not Protocol Buffers API
197 return null;
198 }
199  
200 /**
201 * Check if a given Riak Object have expired.
202 *
203 * @param \Riak\Object $object
204 *
205 * @return bool
206 */
207 private function isExpired(Object $object)
208 {
209 $metadataMap = $object->getMetadataMap();
210  
211 return isset($metadataMap[self::EXPIRES_HEADER])
212 && $metadataMap[self::EXPIRES_HEADER] < time();
213 }
214  
215 /**
216 * On-read conflict resolution. Applied approach here is last write wins.
217 * Specific needs may override this method to apply alternate conflict resolutions.
218 *
219 * {@internal Riak does not attempt to resolve a write conflict, and store
220 * it as sibling of conflicted one. By following this approach, it is up to
221 * the next read to resolve the conflict. When this happens, your fetched
222 * object will have a list of siblings (read as a list of objects).
223 * In our specific case, we do not care about the intermediate ones since
224 * they are all the same read from storage, and we do apply a last sibling
225 * (last write) wins logic.
226 * If by any means our resolution generates another conflict, it'll up to
227 * next read to properly solve it.}
228 *
229 * @param string $id
230 * @param string $vClock
231 * @param array $objectList
232 *
233 * @return \Riak\Object
234 */
235 protected function resolveConflict($id, $vClock, array $objectList)
236 {
237 // Our approach here is last-write wins
238 $winner = $objectList[count($objectList)];
239  
240 $putInput = new Input\PutInput();
241 $putInput->setVClock($vClock);
242  
243 $mergedObject = new Object($id);
244 $mergedObject->setContent($winner->getContent());
245  
246 $this->bucket->put($mergedObject, $putInput);
247  
248 return $mergedObject;
249 }
250 }