Civi/Api4/Query/SqlFunction.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | Copyright CiviCRM LLC. All rights reserved.                        |
   5  |                                                                    |
   6  | This work is published under the GNU AGPLv3 license with some      |
   7  | permitted exceptions and without any warranty. For full license    |
   8  | and copyright information, see https://civicrm.org/licensing       |
   9  +--------------------------------------------------------------------+
  10  */
  11
  12 namespace Civi\Api4\Query;
  13
  14 /**
  15  * Base class for all Sql functions.
  16  *
  17  * @package Civi\Api4\Query
  18  */
  19 abstract class SqlFunction extends SqlExpression {
  20
  21   /**
  22    * @var array
  23    */
  24   protected static $params = [];
  25
  26   /**
  27    * @var array[]
  28    */
  29   protected $args = [];
  30
  31   /**
  32    * Used for categorizing functions in the UI
  33    *
  34    * @var string
  35    */
  36   protected static $category;
  37
  38   const CATEGORY_AGGREGATE = 'aggregate',
  39     CATEGORY_COMPARISON = 'comparison',
  40     CATEGORY_DATE = 'date',
  41     CATEGORY_MATH = 'math',
  42     CATEGORY_STRING = 'string';
  43
  44   /**
  45    * Parse the argument string into an array of function arguments
  46    */
  47   protected function initialize() {
  48     $arg = trim(substr($this->expr, strpos($this->expr, '(') + 1, -1));
  49     foreach ($this->getParams() as $idx => $param) {
  50       $prefix = $this->captureKeyword($param['prefix'], $arg);
  51       $this->args[$idx] = [
  52         'prefix' => $prefix,
  53         'expr' => [],
  54         'suffix' => NULL,
  55       ];
  56       if ($param['expr'] && isset($prefix) || in_array('', $param['prefix']) || !$param['optional']) {
  57         $this->args[$idx]['expr'] = $this->captureExpressions($arg, $param['expr'], $param['must_be'], $param['cant_be']);
  58         $this->args[$idx]['suffix'] = $this->captureKeyword($param['suffix'], $arg);
  59       }
  60     }
  61   }
  62
  63   /**
  64    * Shift a keyword off the beginning of the argument string and return it.
  65    *
  66    * @param array $keywords
  67    *   Whitelist of keywords
  68    * @param string $arg
  69    * @return mixed|null
  70    */
  71   private function captureKeyword($keywords, &$arg) {
  72     foreach (array_filter($keywords) as $key) {
  73       if (strpos($arg, $key . ' ') === 0) {
  74         $arg = ltrim(substr($arg, strlen($key)));
  75         return $key;
  76       }
  77     }
  78     return NULL;
  79   }
  80
  81   /**
  82    * Shifts 0 or more expressions off the argument string and returns them
  83    *
  84    * @param string $arg
  85    * @param int $limit
  86    * @param array $mustBe
  87    * @param array $cantBe
  88    * @return array
  89    * @throws \API_Exception
  90    */
  91   private function captureExpressions(&$arg, $limit, $mustBe, $cantBe) {
  92     $captured = [];
  93     $arg = ltrim($arg);
  94     while ($arg) {
  95       $item = $this->captureExpression($arg);
  96       $arg = ltrim(substr($arg, strlen($item)));
  97       $expr = SqlExpression::convert($item, FALSE, $mustBe, $cantBe);
  98       $this->fields = array_merge($this->fields, $expr->getFields());
  99       $captured[] = $expr;
 100       // Keep going if we have a comma indicating another expression follows
 101       if (count($captured) < $limit && substr($arg, 0, 1) === ',') {
 102         $arg = ltrim(substr($arg, 1));
 103       }
 104       else {
 105         break;
 106       }
 107     }
 108     return $captured;
 109   }
 110
 111   /**
 112    * Scans the beginning of a string for an expression; stops when it hits delimiter
 113    *
 114    * @param $arg
 115    * @return string
 116    */
 117   private function captureExpression($arg) {
 118     $chars = str_split($arg);
 119     $isEscaped = $quote = NULL;
 120     $item = '';
 121     $quotes = ['"', "'"];
 122     $brackets = [
 123       ')' => '(',
 124     ];
 125     $enclosures = array_fill_keys($brackets, 0);
 126     foreach ($chars as $index => $char) {
 127       if (!$isEscaped && in_array($char, $quotes, TRUE)) {
 128         // Open quotes - we'll ignore everything inside
 129         if (!$quote) {
 130           $quote = $char;
 131         }
 132         // Close quotes
 133         elseif ($char === $quote) {
 134           $quote = NULL;
 135         }
 136       }
 137       if (!$quote) {
 138         // Delineates end of expression
 139         if (($char == ',' || $char == ' ') && !array_filter($enclosures)) {
 140           return $item;
 141         }
 142         // Open brackets - we'll ignore delineators inside
 143         if (isset($enclosures[$char])) {
 144           $enclosures[$char]++;
 145         }
 146         // Close brackets
 147         if (isset($brackets[$char]) && $enclosures[$brackets[$char]]) {
 148           $enclosures[$brackets[$char]]--;
 149         }
 150       }
 151       $item .= $char;
 152       // We are escaping the next char if this is a backslash not preceded by an odd number of backslashes
 153       $isEscaped = $char === '\\' && ((strlen($item) - strlen(rtrim($item, '\\'))) % 2);
 154     }
 155     return $item;
 156   }
 157
 158   /**
 159    * Render the expression for insertion into the sql query
 160    *
 161    * @param array $fieldList
 162    * @return string
 163    */
 164   public function render(array $fieldList): string {
 165     $output = '';
 166     $params = $this->getParams();
 167     foreach ($this->args as $index => $arg) {
 168       $rendered = $this->renderArg($arg, $params[$index], $fieldList);
 169       if (strlen($rendered)) {
 170         $output .= (strlen($output) ? ' ' : '') . $rendered;
 171       }
 172     }
 173     return $this->getName() . '(' . $output . ')';
 174   }
 175
 176   /**
 177    * @param array $arg
 178    * @param array $param
 179    * @param array $fieldList
 180    * @return string
 181    */
 182   private function renderArg($arg, $param, $fieldList): string {
 183     // Supply api_default
 184     if (!isset($arg['prefix']) && !isset($arg['suffix']) && empty($arg['expr']) && !empty($param['api_default'])) {
 185       $arg = [
 186         'prefix' => $param['api_default']['prefix'] ?? reset($param['prefix']),
 187         'expr' => array_map([parent::class, 'convert'], $param['api_default']['expr'] ?? []),
 188         'suffix' => $param['api_default']['suffix'] ?? reset($param['suffix']),
 189       ];
 190     }
 191     $rendered = $arg['prefix'] ?? '';
 192     foreach ($arg['expr'] ?? [] as $idx => $expr) {
 193       if (strlen($rendered) || $idx) {
 194         $rendered .= $idx ? ', ' : ' ';
 195       }
 196       $rendered .= $expr->render($fieldList);
 197     }
 198     if (isset($arg['suffix'])) {
 199       $rendered .= (strlen($rendered) ? ' ' : '') . $arg['suffix'];
 200     }
 201     return $rendered;
 202   }
 203
 204   /**
 205    * @inheritDoc
 206    */
 207   public function getAlias(): string {
 208     return $this->alias ?? $this->getName() . ':' . implode('_', $this->fields);
 209   }
 210
 211   /**
 212    * Get the name of this sql function.
 213    * @return string
 214    */
 215   public static function getName(): string {
 216     $className = static::class;
 217     return substr($className, strrpos($className, 'SqlFunction') + 11);
 218   }
 219
 220   /**
 221    * Get the param metadata for this sql function.
 222    * @return array
 223    */
 224   public static function getParams(): array {
 225     $params = [];
 226     foreach (static::$params as $param) {
 227       // Merge in defaults to ensure each param has these properties
 228       $params[] = $param + [
 229         'prefix' => [],
 230         'expr' => 1,
 231         'suffix' => [],
 232         'optional' => FALSE,
 233         'must_be' => [],
 234         'cant_be' => ['SqlWild'],
 235         'api_default' => NULL,
 236       ];
 237     }
 238     return $params;
 239   }
 240
 241   /**
 242    * Get the arguments passed to this sql function instance.
 243    * @return array[]
 244    */
 245   public function getArgs(): array {
 246     return $this->args;
 247   }
 248
 249   /**
 250    * @return string
 251    */
 252   public static function getCategory(): string {
 253     return static::$category;
 254   }
 255
 256   /**
 257    * @return string
 258    */
 259   abstract public static function getTitle(): string;
 260
 261 }