first commit

wp-content/plugins/sitepress-multilingual-cms/classes/class-wpml-db-chunk.php

@@ -0,0 +1,70 @@
+<?php
+
+use PhpMyAdmin\SqlParser\Parser;
+
+class WPML_DB_Chunk {
+	/**
+	 * @var wpdb
+	 */
+	private $wpdb;
+
+	/**
+	 * @var int
+	 */
+	private $chunk_size;
+
+	/**
+	 * @param wpdb $wpdb
+	 * @param int  $chunk_size
+	 */
+	public function __construct( wpdb $wpdb, $chunk_size = 1000 ) {
+		$this->wpdb       = $wpdb;
+		$this->chunk_size = $chunk_size;
+	}
+
+	/**
+	 * @param string $query
+	 * @param array  $args
+	 * @param int    $elements_num
+	 *
+	 * @return array
+	 *
+	 * @throws \InvalidArgumentException
+	 */
+	public function retrieve( $query, $args, $elements_num ) {
+		$this->validate_query( $query );
+		$result = array();
+
+		$offset = 0;
+		while ( $offset < $elements_num ) {
+			$new_query = $query . sprintf( ' LIMIT %d OFFSET %s', $this->chunk_size, $offset );
+			$new_query = $this->wpdb->prepare( $new_query, $args );
+			$rowset    = $this->wpdb->get_results( $new_query, ARRAY_A );
+
+			if ( is_array( $rowset ) && count( $rowset ) ) {
+				$result = array_merge( $result, $rowset );
+			}
+
+			$offset += $this->chunk_size;
+		}
+
+		return $result;
+	}
+
+	/**
+	 * @param string $query
+	 */
+	private function validate_query( $query ) {
+		$parser = new Parser( $query );
+
+		if ( isset( $parser->statements ) ) {
+			wpml_collect( $parser->statements )->each(
+				function( $statement ) {
+					if ( ! empty( $statement->limit ) ) {
+						throw new InvalidArgumentException( "Query can't contain OFFSET or LIMIT keyword" );
+					}
+				}
+			);
+		}
+	}
+}