From 0666dc9c2934b4662be3182bf50ff8b1d4b09bc1 Mon Sep 17 00:00:00 2001
From: Yaroslav Buzko <yaroslav.buzko@c3.ai>
Date: Thu, 9 Oct 2025 22:59:02 -0700
Subject: [PATCH] Add mysqli-backed compatibility layer

---
 classes/app.class.php     |   8 +-
 classes/database.php      |   6 +-
 includes/mysql_compat.php | 169 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 178 insertions(+), 5 deletions(-)
 create mode 100644 includes/mysql_compat.php

diff --git a/classes/app.class.php b/classes/app.class.php
index 02d5c90..299901d 100644
--- a/classes/app.class.php
+++ b/classes/app.class.php
@@ -33,9 +33,11 @@
 require_once dirname(__FILE__) . '/helper.php';
 
 define('APP_DIR', realpath(dirname(__FILE__) . '/..'));
-define('MODULE_DIR', APP_DIR . DIRECTORY_SEPARATOR . 'modules');
-define('CLASS_DIR', APP_DIR . DIRECTORY_SEPARATOR . 'classes');
-define('INCLUDE_DIR', APP_DIR . DIRECTORY_SEPARATOR . 'includes');
+define('MODULE_DIR', APP_DIR . DIRECTORY_SEPARATOR . 'modules');
+define('CLASS_DIR', APP_DIR . DIRECTORY_SEPARATOR . 'classes');
+define('INCLUDE_DIR', APP_DIR . DIRECTORY_SEPARATOR . 'includes');
+
+require_once INCLUDE_DIR . '/mysql_compat.php';
 
 class app
 {
diff --git a/classes/database.php b/classes/database.php
index 5693b8b..b8b8084 100644
--- a/classes/database.php
+++ b/classes/database.php
@@ -28,8 +28,10 @@
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 
-*/
-class database
+*/
+require_once dirname(__FILE__) . '/../includes/mysql_compat.php';
+
+class database
 {
 
 	var $tablePrefix = '';
diff --git a/includes/mysql_compat.php b/includes/mysql_compat.php
new file mode 100644
index 0000000..b7353d4
--- /dev/null
+++ b/includes/mysql_compat.php
@@ -0,0 +1,169 @@
+<?php
+if (function_exists('mysql_connect')) {
+    return;
+}
+
+// Define legacy fetch mode constants when missing.
+if (!defined('MYSQL_ASSOC')) {
+    define('MYSQL_ASSOC', MYSQLI_ASSOC);
+}
+if (!defined('MYSQL_NUM')) {
+    define('MYSQL_NUM', MYSQLI_NUM);
+}
+if (!defined('MYSQL_BOTH')) {
+    define('MYSQL_BOTH', MYSQLI_BOTH);
+}
+
+if (!function_exists('get_magic_quotes_gpc')) {
+    function get_magic_quotes_gpc()
+    {
+        return 0;
+    }
+}
+
+if (!function_exists('get_magic_quotes_runtime')) {
+    function get_magic_quotes_runtime()
+    {
+        return 0;
+    }
+}
+
+if (!function_exists('set_magic_quotes_runtime')) {
+    function set_magic_quotes_runtime($new_value)
+    {
+        return false;
+    }
+}
+
+$GLOBALS['mysql_compat_last_connection'] = null;
+
+function mysql_connect($server = null, $username = null, $password = null, $new_link = false, $client_flags = 0)
+{
+    $link = mysqli_connect($server, $username, $password);
+    if ($link instanceof mysqli) {
+        $GLOBALS['mysql_compat_last_connection'] = $link;
+    }
+    return $link;
+}
+
+function mysql_select_db($database_name, $link_identifier = null)
+{
+    $link = $link_identifier instanceof mysqli ? $link_identifier : mysql_compat_get_link();
+    if (!$link) {
+        return false;
+    }
+    return mysqli_select_db($link, $database_name);
+}
+
+function mysql_query($query, $link_identifier = null)
+{
+    $link = $link_identifier instanceof mysqli ? $link_identifier : mysql_compat_get_link();
+    if (!$link) {
+        return false;
+    }
+    $result = mysqli_query($link, $query);
+    return $result;
+}
+
+function mysql_fetch_object($result, $class_name = 'stdClass', $params = array())
+{
+    if (!($result instanceof mysqli_result)) {
+        return false;
+    }
+    return mysqli_fetch_object($result, $class_name, $params);
+}
+
+function mysql_fetch_row($result)
+{
+    if (!($result instanceof mysqli_result)) {
+        return false;
+    }
+    return mysqli_fetch_row($result);
+}
+
+function mysql_fetch_assoc($result)
+{
+    if (!($result instanceof mysqli_result)) {
+        return false;
+    }
+    return mysqli_fetch_assoc($result);
+}
+
+function mysql_fetch_array($result, $result_type = MYSQL_BOTH)
+{
+    if (!($result instanceof mysqli_result)) {
+        return false;
+    }
+    return mysqli_fetch_array($result, $result_type);
+}
+
+function mysql_num_rows($result)
+{
+    if (!($result instanceof mysqli_result)) {
+        return false;
+    }
+    return mysqli_num_rows($result);
+}
+
+function mysql_real_escape_string($unescaped_string, $link_identifier = null)
+{
+    $link = $link_identifier instanceof mysqli ? $link_identifier : mysql_compat_get_link();
+    if (!$link) {
+        return addslashes($unescaped_string);
+    }
+    return mysqli_real_escape_string($link, (string) $unescaped_string);
+}
+
+function mysql_affected_rows($link_identifier = null)
+{
+    $link = $link_identifier instanceof mysqli ? $link_identifier : mysql_compat_get_link();
+    if (!$link) {
+        return -1;
+    }
+    return mysqli_affected_rows($link);
+}
+
+function mysql_insert_id($link_identifier = null)
+{
+    $link = $link_identifier instanceof mysqli ? $link_identifier : mysql_compat_get_link();
+    if (!$link) {
+        return 0;
+    }
+    return mysqli_insert_id($link);
+}
+
+function mysql_result($result, $row, $field = 0)
+{
+    if (!($result instanceof mysqli_result)) {
+        return false;
+    }
+    if (!mysqli_data_seek($result, $row)) {
+        return false;
+    }
+    $data = mysqli_fetch_array($result, MYSQLI_BOTH);
+    if ($data === null || $data === false) {
+        return false;
+    }
+    if (is_int($field)) {
+        return array_key_exists($field, $data) ? $data[$field] : false;
+    }
+    return array_key_exists($field, $data) ? $data[$field] : false;
+}
+
+function mysql_error($link_identifier = null)
+{
+    $link = $link_identifier instanceof mysqli ? $link_identifier : mysql_compat_get_link();
+    if (!$link) {
+        return mysqli_connect_error();
+    }
+    return mysqli_error($link);
+}
+
+function mysql_compat_get_link()
+{
+    $link = $GLOBALS['mysql_compat_last_connection'] ?? null;
+    if ($link instanceof mysqli) {
+        return $link;
+    }
+    return null;
+}