From d9f688698ce0396466710e5349e70bd7900ba975 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Tue, 28 May 2019 20:01:17 -0700
Subject: [PATCH] rdbms: clean up and refactor ResultWrapper classes

Change-Id: Ib1d71dbbd31e134cf89dca58f7aa77bdddc828c0
---
 .../resultwrapper/FakeResultWrapper.php       | 61 +++++++++++--------
 .../database/resultwrapper/IResultWrapper.php |  4 +-
 .../database/resultwrapper/ResultWrapper.php  | 41 ++++++-------
 3 files changed, 57 insertions(+), 49 deletions(-)

diff --git a/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php b/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php
index aeb5d8de60..3709de7de2 100644
--- a/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php
+++ b/includes/libs/rdbms/database/resultwrapper/FakeResultWrapper.php
@@ -9,10 +9,10 @@ use stdClass;
  * doesn't go anywhere near an actual database.
  */
 class FakeResultWrapper extends ResultWrapper {
-	/** @var stdClass[] $result */
+	/** @var stdClass[]|array[] $result */
 
 	/**
-	 * @param stdClass[] $rows
+	 * @param stdClass[]|array[] $rows
 	 */
 	function __construct( array $rows ) {
 		parent::__construct( null, $rows );
@@ -22,43 +22,52 @@ class FakeResultWrapper extends ResultWrapper {
 		return count( $this->result );
 	}
 
-	function fetchRow() {
-		if ( $this->pos < count( $this->result ) ) {
-			$this->currentRow = $this->result[$this->pos];
-		} else {
-			$this->currentRow = false;
-		}
-		$this->pos++;
-		if ( is_object( $this->currentRow ) ) {
-			return get_object_vars( $this->currentRow );
-		} else {
-			return $this->currentRow;
-		}
+	function fetchObject() {
+		$current = $this->current();
+
+		$this->next();
+
+		return $current;
 	}
 
-	function seek( $row ) {
-		$this->pos = $row;
+	function fetchRow() {
+		$row = $this->valid() ? $this->result[$this->pos] : false;
+
+		$this->next();
+
+		return is_object( $row ) ? (array)$row : $row;
 	}
 
-	function free() {
+	function seek( $pos ) {
+		$this->pos = $pos;
 	}
 
-	function fetchObject() {
-		$this->fetchRow();
-		if ( $this->currentRow ) {
-			return (object)$this->currentRow;
-		} else {
-			return false;
-		}
+	function free() {
+		$this->result = null;
 	}
 
 	function rewind() {
 		$this->pos = 0;
-		$this->currentRow = null;
+	}
+
+	function current() {
+		$row = $this->valid() ? $this->result[$this->pos] : false;
+
+		return is_array( $row ) ? (object)$row : $row;
+	}
+
+	function key() {
+		return $this->pos;
 	}
 
 	function next() {
-		return $this->fetchObject();
+		$this->pos++;
+
+		return $this->current();
+	}
+
+	function valid() {
+		return array_key_exists( $this->pos, $this->result );
 	}
 }
 
diff --git a/includes/libs/rdbms/database/resultwrapper/IResultWrapper.php b/includes/libs/rdbms/database/resultwrapper/IResultWrapper.php
index debf8a27c3..616fed9d13 100644
--- a/includes/libs/rdbms/database/resultwrapper/IResultWrapper.php
+++ b/includes/libs/rdbms/database/resultwrapper/IResultWrapper.php
@@ -52,9 +52,9 @@ interface IResultWrapper extends Iterator {
 	 * Change the position of the cursor in a result object.
 	 * See mysql_data_seek()
 	 *
-	 * @param int $row
+	 * @param int $pos
 	 */
-	public function seek( $row );
+	public function seek( $pos );
 
 	/**
 	 * Free a result object
diff --git a/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php b/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php
index a9befc2bae..b7938ad256 100644
--- a/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php
+++ b/includes/libs/rdbms/database/resultwrapper/ResultWrapper.php
@@ -30,8 +30,8 @@ class ResultWrapper implements IResultWrapper {
 
 	/** @var int */
 	protected $pos = 0;
-	/** @var stdClass|null */
-	protected $currentRow = null;
+	/** @var stdClass|bool|null */
+	protected $currentRow;
 
 	/**
 	 * Create a row iterator from a result resource and an optional Database object
@@ -63,29 +63,16 @@ class ResultWrapper implements IResultWrapper {
 		return $this->getDB()->fetchRow( $this );
 	}
 
-	public function seek( $row ) {
-		$this->getDB()->dataSeek( $this, $row );
+	public function seek( $pos ) {
+		$this->getDB()->dataSeek( $this, $pos );
+		$this->pos = $pos;
 	}
 
 	public function free() {
-		if ( $this->db ) {
-			$this->db = null;
-		}
+		$this->db = null;
 		$this->result = null;
 	}
 
-	/**
-	 * @return IDatabase
-	 * @throws RuntimeException
-	 */
-	private function getDB() {
-		if ( !$this->db ) {
-			throw new RuntimeException( static::class . ' needs a DB handle for iteration.' );
-		}
-
-		return $this->db;
-	}
-
 	function rewind() {
 		if ( $this->numRows() ) {
 			$this->getDB()->dataSeek( $this, 0 );
@@ -95,8 +82,8 @@ class ResultWrapper implements IResultWrapper {
 	}
 
 	function current() {
-		if ( is_null( $this->currentRow ) ) {
-			$this->next();
+		if ( $this->currentRow === null ) {
+			$this->currentRow = $this->fetchObject();
 		}
 
 		return $this->currentRow;
@@ -116,6 +103,18 @@ class ResultWrapper implements IResultWrapper {
 	function valid() {
 		return $this->current() !== false;
 	}
+
+	/**
+	 * @return IDatabase
+	 * @throws RuntimeException
+	 */
+	private function getDB() {
+		if ( !$this->db ) {
+			throw new RuntimeException( static::class . ' needs a DB handle for iteration.' );
+		}
+
+		return $this->db;
+	}
 }
 
 /**
-- 
2.20.1