[FEATURE] Add Firebird SQL support

docs/engines.md

@@ -45,3 +45,8 @@ converts boolean values into small integers because SQLite does not have
 a separate boolean storage class. Instead, boolean values are stored as
 integers: `0` (false) and `1` (true).
 
+## Firebird Engine
+
+The Firebird Engine is `Latitude\QueryBuilder\Engine\FirebirdEngine`. This engine
+adheres to the SQL-92, with the only custom implementation being limit and offset.
+The returning clause is also added to `INSERT` and `DELETE` queries.

src/Engine/FirebirdEngine.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Engine;
+
+use Latitude\QueryBuilder\Query;
+
+class FirebirdEngine extends CommonEngine
+{
+    public function makeSelect(): Query\SelectQuery
+    {
+        return new Query\Firebird\SelectQuery($this);
+    }
+
+    public function makeInsert(): Query\InsertQuery
+    {
+        return new Query\Firebird\InsertQuery($this);
+    }
+
+    public function makeDelete(): Query\DeleteQuery
+    {
+        return new Query\Firebird\DeleteQuery($this);
+    }
+}

src/Query/Firebird/DeleteQuery.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\ExpressionInterface;
+use Latitude\QueryBuilder\Query;
+
+use Latitude\QueryBuilder\Query\Capability\HasReturning;
+use function is_int;
+use function Latitude\QueryBuilder\literal;
+
+class DeleteQuery extends Query\DeleteQuery
+{
+    use HasReturning;
+
+    public function asExpression(): ExpressionInterface
+    {
+        $query = parent::asExpression();
+        $query = $this->applyReturning($query);
+
+        return $query;
+    }
+
+    protected function applyLimit(ExpressionInterface $query): ExpressionInterface
+    {
+        if (!is_int($this->limit)) {
+            return $query;
+        }
+
+        return $query->append('ROWS %s', literal($this->limit));
+    }
+}

src/Query/Firebird/InsertQuery.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\ExpressionInterface;
+use Latitude\QueryBuilder\Query;
+
+class InsertQuery extends Query\InsertQuery
+{
+    use Query\Capability\HasReturning;
+
+    public function asExpression(): ExpressionInterface
+    {
+        $query = parent::asExpression();
+        $query = $this->applyReturning($query);
+
+        return $query;
+    }
+}

src/Query/Firebird/SelectQuery.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\ExpressionInterface;
+use Latitude\QueryBuilder\Query;
+
+use function is_int;
+use function Latitude\QueryBuilder\literal;
+
+class SelectQuery extends Query\SelectQuery
+{
+    protected function applyOffset(ExpressionInterface $query): ExpressionInterface
+    {
+        if (!is_int($this->limit) || !is_int($this->offset)) {
+            return $query;
+        }
+
+        $rows = $this->offset + 1;
+        $to = $rows + $this->limit - 1;
+
+        return $query->append('ROWS %d TO %d', literal($rows), literal($to));
+    }
+
+    protected function applyLimit(ExpressionInterface $query): ExpressionInterface
+    {
+        if (!is_int($this->limit)) {
+            return $query;
+        }
+
+        // When offset is present, ROWS acts differently and should be handled in ->applyOffset()
+        if (is_int($this->offset)) {
+            return $query;
+        }
+
+        return $query->append('ROWS %s', literal($this->limit));
+    }
+}

tests/Engine/FirebirdTest.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Engine;
+
+use Latitude\QueryBuilder\TestCase;
+
+use function Latitude\QueryBuilder\identify;
+
+class FirebirdTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        $this->engine = new FirebirdEngine();
+    }
+
+    public function testIdentifier(): void
+    {
+        $field = identify('id');
+
+        $this->assertSql('"id"', $field);
+
+        $field = identify('contains"quotes');
+
+        $this->assertSql('"contains""quotes"', $field);
+    }
+}

tests/Query/Firebird/DeleteTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\TestCase;
+
+class DeleteTest extends TestCase
+{
+    use FirebirdEngineSetup;
+
+    public function testLimit(): void
+    {
+        $delete = $this->factory
+            ->delete('users')
+            ->limit(10);
+
+        $this->assertSql('DELETE FROM "users" ROWS 10', $delete);
+        $this->assertParams([], $delete);
+    }
+
+    public function testLimitWithReturning(): void
+    {
+        $delete = $this->factory
+            ->delete('users')
+            ->limit(10)
+            ->returning('id');
+
+        $this->assertSql('DELETE FROM "users" ROWS 10 RETURNING "id"', $delete);
+        $this->assertParams([], $delete);
+    }
+}

tests/Query/Firebird/FirebirdEngineSetup.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\Engine;
+use Latitude\QueryBuilder\EngineInterface;
+
+trait FirebirdEngineSetup
+{
+    protected function getEngine(): EngineInterface
+    {
+        return new Engine\FirebirdEngine();
+    }
+}

tests/Query/Firebird/InsertTest.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\TestCase;
+
+class InsertTest extends TestCase
+{
+    use FirebirdEngineSetup;
+
+    public function testReturning(): void
+    {
+        $insert = $this->factory
+            ->insert('users', [
+                'username' => 'jay',
+            ])
+            ->returning('id');
+
+        $this->assertSql('INSERT INTO "users" ("username") VALUES (?) RETURNING "id"', $insert);
+        $this->assertParams(['jay'], $insert);
+    }
+}

tests/Query/Firebird/SelectTest.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Latitude\QueryBuilder\Query\Firebird;
+
+use Latitude\QueryBuilder\TestCase;
+
+class SelectTest extends TestCase
+{
+    use FirebirdEngineSetup;
+
+    public function testLimitWithoutOffset(): void
+    {
+        $select = $this->factory
+            ->select()
+            ->from('users')
+            ->limit(10);
+
+        $this->assertSql('SELECT * FROM "users" ROWS 10', $select);
+        $this->assertParams([], $select);
+    }
+
+    public function testLimitWithOffset(): void
+    {
+        $select = $this->factory
+            ->select()
+            ->from('users')
+            ->offset(5)
+            ->limit(10);
+
+        $this->assertSql('SELECT * FROM "users" ROWS 6 TO 15', $select);
+        $this->assertParams([], $select);
+    }
+}