Use LoaderException instead of generic Exception for loader errors

This make it easier to handle the errors and could help with
phpmyadmin/phpmyadmin#12791

Signed-off-by: Michal Čihař <[email protected]>

Author: nijel

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+* Use custom LoaderException for context loading errors.
+
 ## [4.1.9] - 2017-07-12
 
 * Various code cleanups.

src/Context.php

@@ -9,6 +9,8 @@
 
 namespace PhpMyAdmin\SqlParser;
 
+use PhpMyAdmin\SqlParser\Exceptions\LoaderException;
+
 /**
  * Holds the configuration of the context that is currently used.
  *
@@ -443,7 +445,7 @@ public static function isSeparator($str)
      * @param string $context name of the context or full class name that
      *                        defines the context
      *
-     * @throws \Exception if the specified context doesn't exist
+     * @throws LoaderException if the specified context doesn't exist
      */
     public static function load($context = '')
     {
@@ -455,8 +457,9 @@ public static function load($context = '')
             $context = self::$contextPrefix . $context;
         }
         if (!class_exists($context)) {
-            throw new \Exception(
-                'Specified context ("' . $context . '") does not exist.'
+            throw new LoaderException(
+                'Specified context ("' . $context . '") does not exist.',
+                $context
             );
         }
         self::$loadedContext = $context;
@@ -491,7 +494,7 @@ public static function loadClosest($context = '')
             try {
                 // Trying to load the new context.
                 static::load($context);
-            } catch (\Exception $e) {
+            } catch (LoaderException $e) {
                 // If it didn't work, we are looking for a new one and skipping
                 // over to the next generation that will try the new context.
                 $context = preg_replace(

src/Exceptions/LoaderException.php

@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * Exception thrown by the lexer.
+ */
+
+namespace PhpMyAdmin\SqlParser\Exceptions;
+
+/**
+ * Exception thrown by the lexer.
+ *
+ * @category   Exceptions
+ *
+ * @license    https://www.gnu.org/licenses/gpl-2.0.txt GPL-2.0+
+ */
+class LoaderException extends \Exception
+{
+    /**
+     * The failed load name.
+     *
+     * @var string
+     */
+    public $name;
+
+    /**
+     * Constructor.
+     *
+     * @param string $msg  the message of this exception
+     * @param string $ch   the character that produced this exception
+     * @param int    $pos  the position of the character
+     * @param int    $code the code of this error
+     */
+    public function __construct($msg = '', $name = '', $code = 0)
+    {
+        parent::__construct($msg, $code);
+        $this->name = $name;
+    }
+}