Generic AST extractor

CHANGELOG.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- [GH#22](https://github.com/jolicode/automapper/pull/22) Added generic AST extractor
+
 ### Changed
 - [GH#19](https://github.com/jolicode/automapper/pull/19) Use attributes everywhere instead of annotations
 

src/Exception/CircularReferenceException.php

@@ -2,15 +2,6 @@
 
 declare(strict_types=1);
 
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <[email protected]>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
 namespace AutoMapper\Exception;
 
 /**

src/Exception/CompileException.php

@@ -2,15 +2,6 @@
 
 declare(strict_types=1);
 
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <[email protected]>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
 namespace AutoMapper\Exception;
 
 /**

src/Exception/InvalidArgumentException.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Exception;
+
+/**
+ * @author Baptiste Leduc <[email protected]>
+ */
+final class InvalidArgumentException extends \InvalidArgumentException
+{
+}

src/Exception/InvalidMappingException.php

@@ -2,15 +2,6 @@
 
 declare(strict_types=1);
 
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <[email protected]>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
 namespace AutoMapper\Exception;
 
 /**

src/Exception/LogicException.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Exception;
+
+/**
+ * @author Baptiste Leduc <[email protected]>
+ */
+final class LogicException extends \LogicException
+{
+}

src/Exception/NoMappingFoundException.php

@@ -2,15 +2,6 @@
 
 declare(strict_types=1);
 
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <[email protected]>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
 namespace AutoMapper\Exception;
 
 /**

src/Extractor/AstExtractor.php

@@ -0,0 +1,114 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Extractor;
+
+use AutoMapper\Exception\InvalidArgumentException;
+use AutoMapper\Exception\LogicException;
+use AutoMapper\Exception\RuntimeException;
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Identifier;
+use PhpParser\Node\Param;
+use PhpParser\Node\Stmt;
+use PhpParser\Parser;
+use PhpParser\ParserFactory;
+
+/**
+ * @author Nicolas Philippe <[email protected]>
+ * @author Baptiste Leduc <[email protected]>
+ *
+ * @internal
+ */
+final readonly class AstExtractor
+{
+    private Parser $parser;
+
+    public function __construct(?Parser $parser = null)
+    {
+        $this->parser = $parser ?? (new ParserFactory())->create(ParserFactory::PREFER_PHP7);
+    }
+
+    /**
+     * Extracts the code of the given method from a given class, and wraps it inside a closure, in order to inject it
+     * in the generated mappers.
+     *
+     * @param class-string $class
+     * @param Arg[]        $inputParameters
+     */
+    public function extract(string $class, string $method, array $inputParameters): Expr
+    {
+        $fileName = (new \ReflectionClass($class))->getFileName();
+        if (false === $fileName) {
+            throw new RuntimeException("You cannot extract code from \"{$class}\" class.");
+        }
+        $fileContents = file_get_contents($fileName);
+        if (false === $fileContents) {
+            throw new RuntimeException("File \"{$fileName}\" for \"{$class}\" couldn't be read.");
+        }
+
+        $statements = $this->parser->parse($fileContents);
+        if (null === $statements) {
+            throw new RuntimeException("Couldn't parse file \"{$fileName}\" for class \"{$class}\".");
+        }
+
+        $namespaceStatement = self::findUnique(Stmt\Namespace_::class, $statements, $fileName);
+        /** @var Stmt\Class_ $classStatement */
+        $classStatement = self::findUnique(Stmt\Class_::class, $namespaceStatement->stmts, $fileName);
+
+        $classMethod = $classStatement->getMethod($method) ?? throw new LogicException("Cannot find method \"{$method}()\" in class \"{$class}\".");
+
+        if (\count($inputParameters) !== \count($classMethod->getParams())) {
+            throw new InvalidArgumentException("Input parameters and method parameters in class \"{$class}\" do not match.");
+        }
+
+        foreach ($classMethod->getParams() as $key => $parameter) {
+            /** @var Expr\Variable $inputParameterValue */
+            $inputParameterValue = $inputParameters[$key]->value;
+
+            if ($parameter->var instanceof Expr\Variable && $inputParameterValue->name !== $parameter->var->name) {
+                $parameterName = \is_string($parameter->var->name) ? $parameter->var->name : 'N/A';
+                throw new InvalidArgumentException("Method parameter \"{$parameterName}\" does not match type \"{$inputParameters[$key]->getType()}\" from input parameter \"{$inputParameters[$key]->name}\" in \"{$class}::{$method}\" method.");
+            }
+        }
+
+        $closureParameters = [];
+        foreach ($classMethod->getParams() as $parameter) {
+            if ($parameter->var instanceof Expr\Variable && $parameter->type instanceof Identifier) {
+                $closureParameters[] = new Param(new Expr\Variable($parameter->var->name), type: $parameter->type->name);
+            }
+        }
+
+        return new Expr\FuncCall(
+            new Expr\Closure([
+                'stmts' => $classMethod->stmts,
+                'params' => $closureParameters,
+                'returnType' => $classMethod->returnType,
+            ]),
+            $inputParameters,
+        );
+    }
+
+    /**
+     * @template T of Stmt
+     *
+     * @param class-string<T> $searchedStatementClass
+     * @param Stmt[]          $statements
+     *
+     * @return T
+     */
+    private static function findUnique(string $searchedStatementClass, array $statements, string $fileName): Stmt
+    {
+        $foundStatements = array_filter(
+            $statements,
+            static fn (Stmt $statement): bool => $statement instanceof $searchedStatementClass,
+        );
+
+        if (\count($foundStatements) > 1) {
+            throw new InvalidArgumentException("Multiple \"{$searchedStatementClass}\" found in file \"{$fileName}\".");
+        }
+
+        return array_values($foundStatements)[0] ?? throw new InvalidArgumentException("No \"{$searchedStatementClass}\" found in file \"{$fileName}\".");
+    }
+}

tests/Extractor/AstExtractorTest.php

@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Tests\Extractor;
+
+use AutoMapper\Exception\InvalidArgumentException;
+use AutoMapper\Exception\RuntimeException;
+use AutoMapper\Extractor\AstExtractor;
+use AutoMapper\Tests\Extractor\Fixtures\Foo;
+use AutoMapper\Tests\Extractor\Fixtures\FooCustomMapper;
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Stmt\Expression;
+use PhpParser\PrettyPrinter\Standard;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @author Baptiste Leduc <[email protected]>
+ */
+class AstExtractorTest extends TestCase
+{
+    public function testExtractSimpleMethod(): void
+    {
+        $extractor = new AstExtractor();
+        $extractedMethod = new Expression($extractor->extract(FooCustomMapper::class, 'transform', [new Arg(new Variable('object'))]));
+
+        $this->assertEquals(<<<PHP
+(function (mixed \$object) : mixed {
+    if (\$object instanceof Foo) {
+        \$object->bar = 'Hello World!';
+    }
+    return \$object;
+})(\$object);
+PHP, $generatedCode = (new Standard())->prettyPrint([$extractedMethod]));
+
+        $codeToEval = <<<PHP
+class Foo
+{
+    public string \$bar;
+    public string \$baz;
+}
+
+\$object = new Foo();
+\$object->bar = 'Hello';
+
+{$generatedCode}
+
+return \$object;
+PHP;
+
+        /** @var Foo $object */
+        $object = eval($codeToEval);
+        $this->assertEquals('Hello World!', $object->bar);
+    }
+
+    public function testCannotExtractCode(): void
+    {
+        $coreClass = \Generator::class;
+
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage("You cannot extract code from \"{$coreClass}\" class.");
+
+        $extractor = new AstExtractor();
+        $extractor->extract($coreClass, 'rewind', [new Arg(new Variable('object'))]);
+    }
+
+    public function testInvalidInputParameters(): void
+    {
+        $class = FooCustomMapper::class;
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage("Input parameters and method parameters in class \"{$class}\" do not match.");
+
+        $extractor = new AstExtractor();
+        $extractor->extract($class, 'transform', [new Arg(new Variable('object')), new Arg(new Variable('context'))]);
+    }
+
+    public function testInvalidExtractedMethodParameters(): void
+    {
+        $class = FooCustomMapper::class;
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage("Input parameters and method parameters in class \"{$class}\" do not match.");
+
+        $extractor = new AstExtractor();
+        $extractor->extract($class, 'switch', [new Arg(new Variable('object'))]);
+    }
+}

tests/Extractor/Fixtures/Foo.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Tests\Extractor\Fixtures;
+
+class Foo
+{
+    public string $bar;
+    public string $baz;
+}

tests/Extractor/Fixtures/FooCustomMapper.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Tests\Extractor\Fixtures;
+
+class FooCustomMapper
+{
+    public function transform(mixed $object): mixed
+    {
+        if ($object instanceof Foo) {
+            $object->bar = 'Hello World!';
+        }
+
+        return $object;
+    }
+
+    public function switch(mixed $object, array $context): mixed
+    {
+        if ($object instanceof Foo) {
+            $object->bar = 'Hello World!';
+        }
+
+        return $object;
+    }
+}