Implement a special field2 function, to migitiate the argument count limit in sqlite

This fixes issue #332 on SQLite DBs

config/packages/doctrine.yaml

@@ -38,7 +38,7 @@ doctrine:
             string_functions:
                 regexp: DoctrineExtensions\Query\Mysql\Regexp
                 ifnull: DoctrineExtensions\Query\Mysql\IfNull
-                field: DoctrineExtensions\Query\Mysql\Field
+                field: App\Doctrine\Functions\CustomField
 
 when@test:
     doctrine:

src/Doctrine/Functions/CustomField.php

@@ -0,0 +1,114 @@
+<?php
+/*
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ *  Copyright (C) 2019 - 2023 Jan Böhmer (https://github.com/jbtronics)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published
+ *  by the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+
+namespace App\Doctrine\Functions;
+
+use Doctrine\DBAL\Platforms\AbstractMySQLPlatform;
+use Doctrine\DBAL\Platforms\SqlitePlatform;
+use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\Node;
+use Doctrine\ORM\Query\Lexer;
+use Doctrine\ORM\Query\Parser;
+use Doctrine\ORM\Query\SqlWalker;
+use DoctrineExtensions\Query\Mysql\Field;
+
+class CustomField extends Field
+{
+
+    protected Node|null|string $field = null;
+
+    protected array $values = [];
+
+
+    public function parse(\Doctrine\ORM\Query\Parser $parser): void
+    {
+        //If we are on MySQL, we can just call the parent method, as these values are not needed in that class then
+        if ($parser->getEntityManager()->getConnection()->getDatabasePlatform() instanceof AbstractMySQLPlatform) {
+            parent::parse($parser);
+            return;
+        }
+
+        //Otherwise we have to do the same as the parent class, so we can use the same getSql method
+        $parser->match(Lexer::T_IDENTIFIER);
+        $parser->match(Lexer::T_OPEN_PARENTHESIS);
+
+        // Do the field.
+        $this->field = $parser->ArithmeticPrimary();
+
+        // Add the strings to the values array. FIELD must
+        // be used with at least 1 string not including the field.
+
+        $lexer = $parser->getLexer();
+
+        while (count($this->values) < 1 ||
+            $lexer->lookahead['type'] != Lexer::T_CLOSE_PARENTHESIS) {
+            $parser->match(Lexer::T_COMMA);
+            $this->values[] = $parser->ArithmeticPrimary();
+        }
+
+        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
+    }
+
+    public function getSql(SqlWalker $sqlWalker): string
+    {
+        //If we are on MySQL, we can use the builtin FIELD function and just call the parent method
+        if ($sqlWalker->getConnection()->getDatabasePlatform() instanceof AbstractMySQLPlatform) {
+            return parent::getSql($sqlWalker);
+        }
+
+        //When we are on SQLite, we have to emulate it with the FIELD2 function
+        if ($sqlWalker->getConnection()->getDatabasePlatform() instanceof SqlitePlatform) {
+            return $this->getSqlForSQLite($sqlWalker);
+        }
+
+        throw new \LogicException('Unsupported database platform');
+    }
+
+    /**
+     * Very similar to the parent method, but uses custom implmented FIELD2 function, which takes the values as a comma separated list
+     * instead of an array to migigate the argument count limit of SQLite.
+     * @param  SqlWalker  $sqlWalker
+     * @return string
+     * @throws \Doctrine\ORM\Query\AST\ASTException
+     */
+    private function getSqlForSQLite(SqlWalker $sqlWalker): string
+    {
+        $query = 'FIELD2(';
+
+        $query .= $this->field->dispatch($sqlWalker);
+
+        $query .= ', "';
+
+        for ($i = 0, $iMax = count($this->values); $i < $iMax; $i++) {
+            if ($i > 0) {
+                $query .= ',';
+            }
+
+            $query .= $this->values[$i]->dispatch($sqlWalker);
+        }
+
+        $query .= '")';
+
+        return $query;
+    }
+}

src/Doctrine/SQLiteRegexExtension.php

@@ -47,8 +47,9 @@ class SQLiteRegexExtension
 
             //Ensure that the function really exists on the connection, as it is marked as experimental according to PHP documentation
             if($native_connection instanceof \PDO && method_exists($native_connection, 'sqliteCreateFunction' )) {
-                $native_connection->sqliteCreateFunction('REGEXP', $this->regexp(...), 2);
-                $native_connection->sqliteCreateFunction('FIELD', $this->field(...));
+                $native_connection->sqliteCreateFunction('REGEXP', $this->regexp(...), 2, \PDO::SQLITE_DETERMINISTIC);
+                $native_connection->sqliteCreateFunction('FIELD', $this->field(...), -1, \PDO::SQLITE_DETERMINISTIC);
+                $native_connection->sqliteCreateFunction('FIELD2', $this->field2(...), 2, \PDO::SQLITE_DETERMINISTIC);
             }
         }
     }
@@ -68,6 +69,19 @@ class SQLiteRegexExtension
         }
     }
 
+    /**
+     * Very similar to the field function, but takes the array values as a comma separated string.
+     * This is needed as SQLite has a pretty low argument count limit.
+     * @param  string|int|null  $value
+     * @param  string  $imploded_array
+     * @return int
+     */
+    private function field2(string|int|null $value, string $imploded_array): int
+    {
+        $array = explode(',', $imploded_array);
+        return $this->field($value, ...$array);
+    }
+
     /**
      * This function emulates the MySQL field function for SQLite
      * This function returns the index (position) of the first argument in the subsequent arguments.#