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tools/parser_sql/processors/OrderByProcessor.php

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+<?php
+/**
+ * OrderByProcessor.php
+ *
+ * This file implements the processor for the ORDER-BY statements.
+ *
+ * Copyright (c) 2010-2012, Justin Swanhart
+ * with contributions by André Rothe <arothe@phosco.info, phosco@gmx.de>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ */
+
+require_once(dirname(__FILE__) . '/AbstractProcessor.php');
+require_once(dirname(__FILE__) . '/SelectExpressionProcessor.php');
+require_once(dirname(__FILE__) . '/../utils/ExpressionType.php');
+
+/**
+ * 
+ * This class processes the ORDER-BY statements.
+ * 
+ * @author arothe
+ * 
+ */
+class OrderByProcessor extends AbstractProcessor {
+
+    private $selectExpressionProcessor;
+
+    public function __construct() {
+        $this->selectExpressionProcessor = new SelectExpressionProcessor();
+    }
+
+    protected function initParseInfo() {
+        return array('base_expr' => "", 'dir' => "ASC", 'expr_type' => ExpressionType::EXPRESSION);
+    }
+
+    protected function processOrderExpression(&$parseInfo, $select) {
+        $parseInfo['base_expr'] = trim($parseInfo['base_expr']);
+
+        if ($parseInfo['base_expr'] === "") {
+            return false;
+        }
+
+        if (is_numeric($parseInfo['base_expr'])) {
+            $parseInfo['expr_type'] = ExpressionType::POSITION;
+        } else {
+            $parseInfo['no_quotes'] = $this->revokeQuotation($parseInfo['base_expr']);
+            // search to see if the expression matches an alias
+            foreach ($select as $clause) {
+                if (!$clause['alias']) {
+                    continue;
+                }
+
+                if ($clause['alias']['no_quotes'] === $parseInfo['no_quotes']) {
+                    $parseInfo['expr_type'] = ExpressionType::ALIAS;
+                    break;
+                }
+            }
+        }
+
+        if ($parseInfo['expr_type'] === ExpressionType::EXPRESSION) {
+            $expr = $this->selectExpressionProcessor->process($parseInfo['base_expr']);
+            $expr['direction'] = $parseInfo['dir'];
+            unset($expr['alias']);
+            return $expr;
+        }
+
+        $result = array();
+        $result['expr_type'] = $parseInfo['expr_type'];
+        $result['base_expr'] = $parseInfo['base_expr'];
+        if (isset($parseInfo['no_quotes'])) {
+            $result['no_quotes'] = $parseInfo['no_quotes'];
+        }
+        $result['direction'] = $parseInfo['dir'];
+        return $result;
+    }
+
+    public function process($tokens, $select = array()) {
+        $out = array();
+        $parseInfo = $this->initParseInfo();
+
+        if (!$tokens) {
+            return false;
+        }
+
+        foreach ($tokens as $token) {
+            $upper = strtoupper(trim($token));
+            switch ($upper) {
+            case ',':
+                $out[] = $this->processOrderExpression($parseInfo, $select);
+                $parseInfo = $this->initParseInfo();
+                break;
+
+            case 'DESC':
+                $parseInfo['dir'] = "DESC";
+                break;
+
+            case 'ASC':
+                $parseInfo['dir'] = "ASC";
+                break;
+
+            default:
+                $parseInfo['base_expr'] .= $token;
+            }
+        }
+
+        $out[] = $this->processOrderExpression($parseInfo, $select);
+        return $out;
+    }
+}
+?>