<?php 
namespace Aws\S3; 
 
use Aws\AwsClientInterface; 
use Aws\S3\Exception\DeleteMultipleObjectsException; 
use GuzzleHttp\Promise; 
use GuzzleHttp\Promise\PromisorInterface; 
use GuzzleHttp\Promise\PromiseInterface; 
 
/** 
 * Efficiently deletes many objects from a single Amazon S3 bucket using an 
 * iterator that yields keys. Deletes are made using the DeleteObjects API 
 * operation. 
 * 
 *     $s3 = new Aws\S3\Client([ 
 *         'region' => 'us-west-2', 
 *         'version' => 'latest' 
 *     ]); 
 * 
 *     $listObjectsParams = ['Bucket' => 'foo', 'Prefix' => 'starts/with/']; 
 *     $delete = Aws\S3\BatchDelete::fromListObjects($s3, $listObjectsParams); 
 *     // Asynchronously delete 
 *     $promise = $delete->promise(); 
 *     // Force synchronous completion 
 *     $delete->delete(); 
 * 
 * When using one of the batch delete creational static methods, you can supply 
 * an associative array of options: 
 * 
 * - before: Function invoked before executing a command. The function is 
 *   passed the command that is about to be executed. This can be useful 
 *   for logging, adding custom request headers, etc. 
 * - batch_size: The size of each delete batch. Defaults to 1000. 
 * 
 * @link http://docs.aws.amazon.com/AmazonS3/latest/API/multiobjectdeleteapi.html 
 */ 
class BatchDelete implements PromisorInterface 
{ 
    private $bucket; 
    /** @var AwsClientInterface */ 
    private $client; 
    /** @var callable */ 
    private $before; 
    /** @var PromiseInterface */ 
    private $cachedPromise; 
    /** @var callable */ 
    private $promiseCreator; 
    private $batchSize = 1000; 
    private $queue = []; 
 
    /** 
     * Creates a BatchDelete object from all of the paginated results of a 
     * ListObjects operation. Each result that is returned by the ListObjects 
     * operation will be deleted. 
     * 
     * @param AwsClientInterface $client            AWS Client to use. 
     * @param array              $listObjectsParams ListObjects API parameters 
     * @param array              $options           BatchDelete options. 
     * 
     * @return BatchDelete 
     */ 
    public static function fromListObjects( 
        AwsClientInterface $client, 
        array $listObjectsParams, 
        array $options = [] 
    ) { 
        $iter = $client->getPaginator('ListObjects', $listObjectsParams); 
        $bucket = $listObjectsParams['Bucket']; 
        $fn = function (BatchDelete $that) use ($iter) { 
            return $iter->each(function ($result) use ($that) { 
                $promises = []; 
                if (is_array($result['Contents'])) { 
                    foreach ($result['Contents'] as $object) { 
                        if ($promise = $that->enqueue($object)) { 
                            $promises[] = $promise; 
                        } 
                    } 
                } 
                return $promises ? Promise\all($promises) : null; 
            }); 
        }; 
 
        return new self($client, $bucket, $fn, $options); 
    } 
 
    /** 
     * Creates a BatchDelete object from an iterator that yields results. 
     * 
     * @param AwsClientInterface $client  AWS Client to use to execute commands 
     * @param string             $bucket  Bucket where the objects are stored 
     * @param \Iterator          $iter    Iterator that yields assoc arrays 
     * @param array              $options BatchDelete options 
     * 
     * @return BatchDelete 
     */ 
    public static function fromIterator( 
        AwsClientInterface $client, 
        $bucket, 
        \Iterator $iter, 
        array $options = [] 
    ) { 
        $fn = function (BatchDelete $that) use ($iter) { 
            return \GuzzleHttp\Promise\coroutine(function () use ($that, $iter) { 
                foreach ($iter as $obj) { 
                    if ($promise = $that->enqueue($obj)) { 
                        yield $promise; 
                    } 
                } 
            }); 
        }; 
 
        return new self($client, $bucket, $fn, $options); 
    } 
 
    public function promise() 
    { 
        if (!$this->cachedPromise) { 
            $this->cachedPromise = $this->createPromise(); 
        } 
 
        return $this->cachedPromise; 
    } 
 
    /** 
     * Synchronously deletes all of the objects. 
     * 
     * @throws DeleteMultipleObjectsException on error. 
     */ 
    public function delete() 
    { 
        $this->promise()->wait(); 
    } 
 
    /** 
     * @param AwsClientInterface $client    Client used to transfer the requests 
     * @param string             $bucket    Bucket to delete from. 
     * @param callable           $promiseFn Creates a promise. 
     * @param array              $options   Hash of options used with the batch 
     * 
     * @throws \InvalidArgumentException if the provided batch_size is <= 0 
     */ 
    private function __construct( 
        AwsClientInterface $client, 
        $bucket, 
        callable $promiseFn, 
        array $options = [] 
    ) { 
        $this->client = $client; 
        $this->bucket = $bucket; 
        $this->promiseCreator = $promiseFn; 
 
        if (isset($options['before'])) { 
            if (!is_callable($options['before'])) { 
                throw new \InvalidArgumentException('before must be callable'); 
            } 
            $this->before = $options['before']; 
        } 
 
        if (isset($options['batch_size'])) { 
            if ($options['batch_size'] <= 0) { 
                throw new \InvalidArgumentException('batch_size is not > 0'); 
            } 
            $this->batchSize = min($options['batch_size'], 1000); 
        } 
    } 
 
    private function enqueue(array $obj) 
    { 
        $this->queue[] = $obj; 
        return count($this->queue) >= $this->batchSize 
            ? $this->flushQueue() 
            : null; 
    } 
 
    private function flushQueue() 
    { 
        static $validKeys = ['Key' => true, 'VersionId' => true]; 
 
        if (count($this->queue) === 0) { 
            return null; 
        } 
 
        $batch = []; 
        while ($obj = array_shift($this->queue)) { 
            $batch[] = array_intersect_key($obj, $validKeys); 
        } 
 
        $command = $this->client->getCommand('DeleteObjects', [ 
            'Bucket' => $this->bucket, 
            'Delete' => ['Objects' => $batch] 
        ]); 
 
        if ($this->before) { 
            call_user_func($this->before, $command); 
        } 
 
        return $this->client->executeAsync($command) 
            ->then(function ($result) { 
                if (!empty($result['Errors'])) { 
                    throw new DeleteMultipleObjectsException( 
                        $result['Deleted'] ?: [], 
                        $result['Errors'] 
                    ); 
                } 
                return $result; 
            }); 
    } 
 
    /** 
     * Returns a promise that will clean up any references when it completes. 
     * 
     * @return PromiseInterface 
     */ 
    private function createPromise() 
    { 
        // Create the promise 
        $promise = call_user_func($this->promiseCreator, $this); 
        $this->promiseCreator = null; 
 
        // Cleans up the promise state and references. 
        $cleanup = function () { 
            $this->before = $this->client = $this->queue = null; 
        }; 
 
        // When done, ensure cleanup and that any remaining are processed. 
        return $promise->then( 
            function () use ($cleanup)  { 
                return Promise\promise_for($this->flushQueue()) 
                    ->then($cleanup); 
            }, 
            function ($reason) use ($cleanup)  { 
                $cleanup(); 
                return Promise\rejection_for($reason); 
            } 
        ); 
    } 
} 
 
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