MRBS 1.12.2 等保2.0二级整改完整提交

包含：登录失败锁定、90天密码有效期、30分钟会话超时、
强制改密、登录审计日志、屏幕水印、企业背景图、
备案信息固定底部、favicon、JS空集合保护、
会话过期体验优化（403 JSON）、display_errors 关闭、
固定 key 根治 Integrity check failed 等全部改动

注意：config.inc.php/.htaccess/.user.ini 含敏感信息，
通过 .gitignore 排除，勿推送到公开仓库。

lib/MRBS/Columns.php

@@ -0,0 +1,168 @@
+<?php
+declare(strict_types=1);
+namespace MRBS;
+
+use Countable;
+use Iterator;
+
+// Holds information about table columns
+// Implemented as a singleton class for performance reasons: it is
+// expensive getting the field info in the constructor.
+class Columns implements Countable, Iterator
+{
+
+  private static $instances = array();
+  private $data;
+  private $index = 0;
+  private $table_name;
+
+
+  private function __construct($table_name)
+  {
+    assert(version_compare(MRBS_MIN_PHP_VERSION, '7.4.0', '<'), "The __wakeup() method is now redundant.");
+    $this->table_name = $table_name;
+    // Get the column info
+    $this->data = db()->field_info($table_name);
+  }
+
+
+  private function __clone()
+  {
+  }
+
+
+  public function __unserialize(array $data) : void
+  {
+    // __unserialize() must have public visibility
+    throw new \Exception("Cannot unserialize a singleton.");
+  }
+
+
+  // __wakeup() is deprecated from PHP 8.5.
+  // "The __wakeup() serialization magic method has been deprecated. Implement __unserialize()
+  // instead (or in addition, if support for old PHP versions is necessary)".
+  // __unserialize() is only available from PHP 7.4.0
+  public function __wakeup()
+  {
+    // __wakeup() must have public visibility
+    throw new \Exception("Cannot unserialize a singleton.");
+  }
+
+
+  public static function getInstance(string $table_name) : Columns
+  {
+    if (!isset(self::$instances[$table_name]))
+    {
+      self::$instances[$table_name] = new self($table_name);
+    }
+
+    return self::$instances[$table_name];
+  }
+
+
+  public function getNames() : array
+  {
+    $result = array();
+
+    foreach ($this as $column)
+    {
+      $result[] = $column->name;
+    }
+
+    return $result;
+  }
+
+
+  public function hasIdColumn() : bool
+  {
+    $column = $this->getColumnByName('id');
+    return isset($column);
+  }
+
+
+  public function getColumnByName(string $name) : ?Column
+  {
+    foreach ($this as $column)
+    {
+      if ($column->name == $name)
+      {
+        return $column;
+      }
+    }
+
+    return null;
+  }
+
+
+  public function current() : Column
+  {
+    $info = $this->data[$this->index];
+    $column = new Column($this->table_name, $info['name']);
+    $column->setLength($info['length']);
+    $column->setDefault($info['default']);
+    $column->setIsNullable($info['is_nullable']);
+    $column->setType($info['type']);
+
+    switch ($info['nature'])
+    {
+      case 'binary':
+        $column->setNature(Column::NATURE_BINARY);
+        break;
+      case 'boolean':
+        $column->setNature(Column::NATURE_BOOLEAN);
+        break;
+      case 'character':
+        $column->setNature(Column::NATURE_CHARACTER);
+        break;
+      case 'decimal':
+        $column->setNature(Column::NATURE_DECIMAL);
+        break;
+      case 'integer':
+        $column->setNature(Column::NATURE_INTEGER);
+        break;
+      case 'json':
+        $column->setNature(Column::NATURE_JSON);
+        break;
+      case 'real':
+        $column->setNature(Column::NATURE_REAL);
+        break;
+      case 'timestamp':
+        $column->setNature(Column::NATURE_TIMESTAMP);
+        break;
+      default:
+        throw new \Exception("Unknown nature '" . $info['nature'] . "'");
+        break;
+    }
+
+    return $column;
+  }
+
+
+  public function next() : void
+  {
+    $this->index++;
+  }
+
+  public function key() : int
+  {
+    return $this->index;
+  }
+
+
+  public function valid() : bool
+  {
+    return isset($this->data[$this->key()]);
+  }
+
+
+  public function rewind() : void
+  {
+    $this->index = 0;
+  }
+
+
+  public function count() : int
+  {
+    return count($this->data);
+  }
+}