Extract Collection::count() to an operation class

src/Collection.php

@@ -17,6 +17,7 @@ use MongoDB\Model\IndexInfoIteratorIterator;
 use MongoDB\Model\IndexInput;
 use MongoDB\Operation\Aggregate;
 use MongoDB\Operation\CreateIndexes;
+use MongoDB\Operation\Count;
 use MongoDB\Operation\Distinct;
 use Traversable;
 
@@ -236,28 +237,19 @@ class Collection
     }
 
     /**
-     * Counts all documents matching $filter
-     * If no $filter provided, returns the numbers of documents in the collection
+     * Gets the number of documents matching the filter.
      *
-     * @see http://docs.mongodb.org/manual/reference/command/count/
-     * @see Collection::getCountOptions() for supported $options
-     *
-     * @param array $filter   The find query to execute
-     * @param array $options  Additional options
+     * @see Count::__construct() for supported options
+     * @param array $filter  Query by which to filter documents
+     * @param array $options Command options
      * @return integer
      */
     public function count(array $filter = array(), array $options = array())
     {
-        $cmd = array(
-            "count" => $this->collname,
-            "query" => (object) $filter,
-        ) + $options;
+        $operation = new Count($this->dbname, $this->collname, $filter, $options);
+        $server = $this->manager->selectServer(new ReadPreference(ReadPreference::RP_PRIMARY));
 
-        $doc = current($this->_runCommand($this->dbname, $cmd)->toArray());
-        if ($doc["ok"]) {
-            return (integer) $doc["n"];
-        }
-        throw $this->_generateCommandException($doc);
+        return $operation->execute($server);
     }
 
     /**
@@ -581,44 +573,6 @@ class Collection
         return $this->collname;
     }
 
-    /**
-     * Retrieves all count options with their default values.
-     *
-     * @return array of Collection::count() options
-     */
-    public function getCountOptions()
-    {
-        return array(
-            /**
-             * The index to use.
-             *
-             * @see http://docs.mongodb.org/manual/reference/command/count/
-             */
-            "hint" => "", // string or document
-
-            /**
-             * The maximum number of documents to count.
-             *
-             * @see http://docs.mongodb.org/manual/reference/command/count/
-             */
-            "limit" => 0,
-
-            /**
-             * The maximum amount of time to allow the query to run.
-             *
-             * @see http://docs.mongodb.org/manual/reference/command/count/
-             */
-            "maxTimeMS" => 0,
-
-            /**
-             * The number of documents to skip before returning the documents.
-             *
-             * @see http://docs.mongodb.org/manual/reference/command/count/
-             */
-            "skip"  => 0,
-        );
-    }
-
     /**
      * Return the database name.
      *

src/Operation/Count.php

+<?php
+
+namespace MongoDB\Operation;
+
+use MongoDB\Driver\Command;
+use MongoDB\Driver\Server;
+use MongoDB\Exception\InvalidArgumentException;
+use MongoDB\Exception\InvalidArgumentTypeException;
+use MongoDB\Exception\RuntimeException;
+use MongoDB\Exception\UnexpectedValueException;
+
+/**
+ * Operation for the count command.
+ *
+ * @api
+ * @see MongoDB\Collection::count()
+ * @see http://docs.mongodb.org/manual/reference/command/count/
+ */
+class Count implements Executable
+{
+    private $databaseName;
+    private $collectionName;
+    private $filter;
+    private $options;
+
+    /**
+     * Constructs a count command.
+     *
+     * Supported options:
+     *
+     *  * hint (string|document): The index to use. If a document, it will be
+     *    interpretted as an index specification and a name will be generated.
+     *
+     *  * limit (integer): The maximum number of documents to count.
+     *
+     *  * maxTimeMS (integer): The maximum amount of time to allow the query to
+     *    run.
+     *
+     *  * skip (integer): The number of documents to skip before returning the
+     *    documents.
+     *
+     * @param string $databaseName   Database name
+     * @param string $collectionName Collection name
+     * @param array  $filter         Query by which to filter documents
+     * @param array  $options        Command options
+     * @throws InvalidArgumentException
+     */
+    public function __construct($databaseName, $collectionName, array $filter = array(), array $options = array())
+    {
+        if (isset($options['hint'])) {
+            if (is_array($options['hint']) || is_object($options['hint'])) {
+                $options['hint'] = $this->generateIndexName($options['hint']);
+            }
+
+            if ( ! is_string($options['hint'])) {
+                throw new InvalidArgumentTypeException('"hint" option', $options['hint'], 'string or array or object');
+            }
+        }
+
+        if (isset($options['limit']) && ! is_integer($options['limit'])) {
+            throw new InvalidArgumentTypeException('"limit" option', $options['limit'], 'integer');
+        }
+
+        if (isset($options['maxTimeMS']) && ! is_integer($options['maxTimeMS'])) {
+            throw new InvalidArgumentTypeException('"maxTimeMS" option', $options['maxTimeMS'], 'integer');
+        }
+
+        if (isset($options['skip']) && ! is_integer($options['skip'])) {
+            throw new InvalidArgumentTypeException('"skip" option', $options['skip'], 'integer');
+        }
+
+        $this->databaseName = (string) $databaseName;
+        $this->collectionName = (string) $collectionName;
+        $this->filter = $filter;
+        $this->options = $options;
+    }
+
+    /**
+     * Execute the operation.
+     *
+     * @see Executable::execute()
+     * @param Server $server
+     * @return integer
+     */
+    public function execute(Server $server)
+    {
+        $cursor = $server->executeCommand($this->databaseName, $this->createCommand());
+        $result = current($cursor->toArray());
+
+        if (empty($result['ok'])) {
+            throw new RuntimeException(isset($result['errmsg']) ? $result['errmsg'] : 'Unknown error');
+        }
+
+        if ( ! isset($result['n']) || ! is_integer($result['n'])) {
+            throw new UnexpectedValueException('count command did not return an "n" integer');
+        }
+
+        return $result['n'];
+    }
+
+    /**
+     * Create the count command.
+     *
+     * @return Command
+     */
+    private function createCommand()
+    {
+        $cmd = array(
+            'count' => $this->collectionName,
+        );
+
+        if ( ! empty($this->filter)) {
+            $cmd['query'] = (object) $this->filter;
+        }
+
+        foreach (array('hint', 'limit', 'maxTimeMS', 'skip') as $option) {
+            if (isset($this->options[$option])) {
+                $cmd[$option] = $this->options[$option];
+            }
+        }
+
+        return new Command($cmd);
+    }
+
+    /**
+     * Generates an index name from its key specification.
+     *
+     * @param array|object $key Document containing fields mapped to values,
+     *                          which denote order or an index type
+     * @return string
+     */
+    private function generateIndexName($key)
+    {
+        $name = '';
+
+        foreach ($key as $field => $type) {
+            $name .= ($name != '' ? '_' : '') . $field . '_' . $type;
+        }
+
+        return $name;
+    }
+}