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https://github.com/predis/predis.git
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Implement PHP iterator for lists based on the LRANGE command.
This iterator tries to mimic the same behaviour of the cursor-based iterators implemented upon the SCAN family of commands and offering only limited guarantees on the returned elements, but uses LRANGE to fetch items from a list incrementally.
This commit is contained in:
Daniele Alessandri
+7
-1
@@ -6,7 +6,13 @@ v0.8.5 (2013-xx-xx)
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- Added `SCAN`, `SSCAN`, `ZSCAN`, `HSCAN` to the server profile for Redis 2.8.
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- Implemented iterator-based abstraction for `SCAN`, `SSCAN`, `ZSCAN`, `HSCAN`.
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- Implemented PHP iterators for incremental iterations over Redis collections:
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- keyspace (cursor-based iterator using `SCAN`)
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- sets (cursor-based iterator using `SSCAN`)
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- sorted sets (cursor-based iterator using `ZSCAN`)
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- hashes (cursor-based iterator using `HSCAN`)
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- lists (plain iterator using `LRANGE`)
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- `Predis\Client::pubSubLoop()` should now be used instead of the deprecated
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`Predis\Client::pubSub()` (which still works like usual to avoid B/C breaks).
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@@ -0,0 +1,174 @@
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<?php
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/*
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* This file is part of the Predis package.
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*
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* (c) Daniele Alessandri <suppakilla@gmail.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Predis\Collection\Iterator;
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use InvalidArgumentException;
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use Iterator;
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use Predis\ClientInterface;
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use Predis\NotSupportedException;
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/**
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* Abstracts the iteration of items stored in a list by leveraging the LRANGE
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* command wrapped in a fully-rewindable PHP iterator.
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*
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* This iterator tries to emulate the behaviour of cursor-based iterators based
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* on the SCAN-family of commands introduced in Redis <= 2.8, meaning that due
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* to its incremental nature with multiple fetches it can only offer limited
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* guarantees on the returned elements because the collection can change several
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* times (trimmed, deleted, overwritten) during the iteration process.
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*
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* @author Daniele Alessandri <suppakilla@gmail.com>
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* @link http://redis.io/commands/lrange
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*/
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class ListKey implements Iterator
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{
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protected $client;
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protected $count;
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protected $key;
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protected $valid;
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protected $fetchmore;
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protected $elements;
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protected $position;
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protected $current;
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/**
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* @param ClientInterface $client Client connected to Redis.
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* @param string $key Redis list key.
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* @param int $count Number of items retrieved on each fetch operation.
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*/
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public function __construct(ClientInterface $client, $key, $count = 10)
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{
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$this->requiredCommand($client, 'LRANGE');
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if ((false === $count = filter_var($count, FILTER_VALIDATE_INT)) || $count < 0) {
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throw new InvalidArgumentException('The $count argument must be a positive integer.');
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}
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$this->client = $client;
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$this->key = $key;
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$this->count = $count;
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$this->reset();
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}
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/**
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* Ensures that the client instance supports the specified Redis
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* command required to fetch elements from the server to perform
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* the iteration.
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*
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* @param ClientInterface Client connected to Redis.
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* @param string $commandID Command ID.
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*/
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protected function requiredCommand(ClientInterface $client, $commandID)
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{
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if (!$client->getProfile()->supportsCommand($commandID)) {
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throw new NotSupportedException("The specified server profile does not support the `$commandID` command.");
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}
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}
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/**
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* Resets the inner state of the iterator.
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*/
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protected function reset()
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{
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$this->valid = true;
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$this->fetchmore = true;
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$this->elements = array();
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$this->position = -1;
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$this->current = null;
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}
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/**
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* Fetches a new set of elements from the remote collection,
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* effectively advancing the iteration process.
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*
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* @return array
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*/
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protected function executeCommand()
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{
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return $this->client->lrange($this->key, $this->position + 1, $this->position + $this->count);
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}
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/**
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* Populates the local buffer of elements fetched from the
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* server during the iteration.
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*/
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protected function fetch()
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{
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$elements = $this->executeCommand();
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if (count($elements) < $this->count) {
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$this->fetchmore = false;
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}
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$this->elements = $elements;
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}
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/**
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* Extracts next values for key() and current().
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*/
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protected function extractNext()
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{
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$this->position++;
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$this->current = array_shift($this->elements);
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}
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/**
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* {@inheritdoc}
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*/
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public function rewind()
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{
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$this->reset();
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$this->next();
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}
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/**
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* {@inheritdoc}
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*/
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public function current()
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{
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return $this->current;
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}
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/**
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* {@inheritdoc}
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*/
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public function key()
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{
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return $this->position;
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}
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/**
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* {@inheritdoc}
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*/
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public function next()
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{
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if (!$this->elements && $this->fetchmore) {
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$this->fetch();
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}
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if ($this->elements) {
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$this->extractNext();
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} else {
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$this->valid = false;
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}
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}
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/**
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* {@inheritdoc}
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*/
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public function valid()
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{
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return $this->valid;
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}
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}
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@@ -0,0 +1,249 @@
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<?php
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/*
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* This file is part of the Predis package.
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*
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* (c) Daniele Alessandri <suppakilla@gmail.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Predis\Collection\Iterator;
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use \PHPUnit_Framework_TestCase as StandardTestCase;
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use Predis\Client;
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use Predis\Profile\ServerProfile;
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/**
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* @group realm-iterators
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*/
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class ListKeyTest extends StandardTestCase
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{
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/**
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* @group disconnected
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*/
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public function testIterationWithNoResults()
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{
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$client = $this->getMock('Predis\Client', array('getProfile', 'lrange'));
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$client->expects($this->once())
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->method('lrange')
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->with('key:list', 0, 9)
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->will($this->returnValue(array()));
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$iterator = new ListKey($client, 'key:list');
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$iterator->rewind();
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$this->assertFalse($iterator->valid());
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}
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/**
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* @group disconnected
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*/
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public function testIterationOnSingleFetch()
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{
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$client = $this->getMock('Predis\Client', array('getProfile', 'lrange'));
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$client->expects($this->once())
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->method('lrange')
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->with('key:list', 0, 9)
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->will($this->returnValue(array('item:1', 'item:2', 'item:3')));
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$iterator = new ListKey($client, 'key:list');
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$iterator->rewind();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:1', $iterator->current());
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$this->assertSame(0, $iterator->key());
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$iterator->next();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:2', $iterator->current());
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$this->assertSame(1, $iterator->key());
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$iterator->next();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:3', $iterator->current());
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$this->assertSame(2, $iterator->key());
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$iterator->next();
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$this->assertFalse($iterator->valid());
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}
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/**
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* @group disconnected
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*/
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public function testIterationOnMultipleFetches()
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{
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$client = $this->getMock('Predis\Client', array('getProfile', 'lrange'));
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$client->expects($this->at(1))
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->method('lrange')
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->with('key:list', 0, 9)
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->will($this->returnValue(array(
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'item:1', 'item:2', 'item:3', 'item:4', 'item:5', 'item:6', 'item:7', 'item:8', 'item:9', 'item:10'
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)));
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$client->expects($this->at(2))
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->method('lrange')
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->with('key:list', 10, 19)
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->will($this->returnValue(array('item:11', 'item:12')));
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$iterator = new ListKey($client, 'key:list');
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for ($i = 1, $iterator->rewind(); $i <= 12; $i++, $iterator->next()) {
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$this->assertTrue($iterator->valid());
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$this->assertSame("item:$i", $iterator->current());
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$this->assertSame($i - 1, $iterator->key());
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}
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$this->assertFalse($iterator->valid());
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}
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/**
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* @group disconnected
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* @expectedException InvalidArgumentException
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* @expectedExceptionMessage The $count argument must be a positive integer.
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*/
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public function testThrowsExceptionOnConstructorWithNonIntegerCountParameter()
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{
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$client = $this->getMock('Predis\ClientInterface');
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$iterator = new ListKey($client, 'key:list', 'wrong');
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}
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/**
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* @group disconnected
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* @expectedException InvalidArgumentException
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* @expectedExceptionMessage The $count argument must be a positive integer.
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*/
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public function testThrowsExceptionOnConstructorWithNegativeCountParameter()
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{
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$client = $this->getMock('Predis\ClientInterface');
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$iterator = new ListKey($client, 'key:list', 'wrong');
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}
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/**
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* @group disconnected
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*/
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public function testIterationWithCountParameter()
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{
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$client = $this->getMock('Predis\Client', array('getProfile', 'lrange'));
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$client->expects($this->at(1))
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->method('lrange')
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->with('key:list', 0, 4)
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->will($this->returnValue(array('item:1', 'item:2')));
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$iterator = new ListKey($client, 'key:list', 5);
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$iterator->rewind();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:1', $iterator->current());
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$this->assertSame(0, $iterator->key());
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$iterator->next();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:2', $iterator->current());
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$this->assertSame(1, $iterator->key());
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$iterator->next();
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$this->assertFalse($iterator->valid());
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}
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/**
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* @group disconnected
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*/
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public function testIterationWithCountParameterOnMultipleFetches()
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{
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$client = $this->getMock('Predis\Client', array('getProfile', 'lrange'));
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$client->expects($this->at(1))
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->method('lrange')
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->with('key:list', 0, 1)
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->will($this->returnValue(array('item:1', 'item:2')));
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$client->expects($this->at(2))
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->method('lrange')
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->with('key:list', 2, 3)
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->will($this->returnValue(array('item:3')));
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$iterator = new ListKey($client, 'key:list', 2);
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$iterator->rewind();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:1', $iterator->current());
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$this->assertSame(0, $iterator->key());
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$iterator->next();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:2', $iterator->current());
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$this->assertSame(1, $iterator->key());
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$iterator->next();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:3', $iterator->current());
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$this->assertSame(2, $iterator->key());
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$iterator->next();
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$this->assertFalse($iterator->valid());
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}
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/**
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* @group disconnected
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*/
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public function testIterationRewindable()
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{
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$client = $this->getMock('Predis\Client', array('getProfile', 'lrange'));
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$client->expects($this->any())
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->method('getProfile')
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->will($this->returnValue(ServerProfile::getDefault()));
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$client->expects($this->exactly(2))
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->method('lrange')
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->with('key:list', 0, 9)
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->will($this->returnValue(array('item:1', 'item:2')));
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$iterator = new ListKey($client, 'key:list');
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$iterator->rewind();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:1', $iterator->current());
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$this->assertSame(0, $iterator->key());
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$iterator->rewind();
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$this->assertTrue($iterator->valid());
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$this->assertSame('item:1', $iterator->current());
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$this->assertSame(0, $iterator->key());
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$iterator->next();
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$this->assertTrue($iterator->valid());
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$this->assertSame(1, $iterator->key());
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$this->assertSame('item:2', $iterator->current());
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$iterator->next();
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$this->assertFalse($iterator->valid());
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}
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}
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