feature #46773 [VarDumper] Add FFI\CData and FFI\CType types (Ser…

…afimArts)

This PR was squashed before being merged into the 6.2 branch.

Discussion
----------

[VarDumper] Add `FFI\CData` and `FFI\CType` types

| Q             | A
| ------------- | ---
| Branch?       | 6.2
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Added support of FFI:
```php
$ffi = \FFI::cdef(<<<'CPP'
    typedef struct { int x; int y; } Point;
    typedef struct Example {
        uint8_t array[32];
        long longVal;
        __extension__ union {
            __extension__ struct { short shortVal; };
            struct { Point point; float e; };
        };
        bool boolValue;
        int (*func)(struct __sub *h);
    } Example;
CPP);

$struct = $ffi->new('Example');
$struct->func = (static fn (object $ptr) => 42);

dump($struct);
```

**Before**

```
FFI\CData {#2}
```

**After**

```
FFI\CData<struct Example> size 64 align 8 {#2
  +array: FFI\CData<uint8_t[32]> size 32 align 1 {#18}
  +int32_t longVal: 0
  +int16_t shortVal: 0
  +point: FFI\CData<struct <anonymous>> size 8 align 4 {#17
    +int32_t x: 0
    +int32_t y: 0
  }
  +float e: 0.0
  +bool boolValue: false
  +func: [cdecl] callable(struct __sub*): int32_t {#20
    returnType: FFI\CType<int32_t> size 4 align 4 {#25}
  }
}
```

P.S. I apologize for the multiple force pushes, errors in tests and codestyle have been fixed.

## Review And TODOs

- Pointers
  - [x] Pointer to scalar tests.
  - [x] Pointer to struct tests.
  - [x] "Special" pointer to `char*` tests (with `\0` and without `\0`).
- Possible Errors
  - [x] Do not dump union fields with pointer references (possible SIGSEGV).

Commits
-------

1c7dc52abb [VarDumper] Add `FFI\CData` and `FFI\CType` types

CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+6.2
+---
+
+ * Add support for `FFI\CData` and `FFI\CType`
+
 5.4
 ---
 

Caster/FFICaster.php

@@ -0,0 +1,161 @@
+<?php
+
+/*
+ * 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 Symfony\Component\VarDumper\Caster;
+
+use FFI\CData;
+use FFI\CType;
+use Symfony\Component\VarDumper\Cloner\Stub;
+
+/**
+ * Casts FFI extension classes to array representation.
+ *
+ * @author Nesmeyanov Kirill <[email protected]>
+ */
+final class FFICaster
+{
+    /**
+     * In case of "char*" contains a string, the length of which depends on
+     * some other parameter, then during the generation of the string it is
+     * possible to go beyond the allowable memory area.
+     *
+     * This restriction serves to ensure that processing does not take
+     * up the entire allowable PHP memory limit.
+     */
+    private const MAX_STRING_LENGTH = 255;
+
+    public static function castCTypeOrCData(CData|CType $data, array $args, Stub $stub): array
+    {
+        if ($data instanceof CType) {
+            $type = $data;
+            $data = null;
+        } else {
+            $type = \FFI::typeof($data);
+        }
+
+        $stub->class = sprintf('%s<%s> size %d align %d', ($data ?? $type)::class, $type->getName(), $type->getSize(), $type->getAlignment());
+
+        return match ($type->getKind()) {
+            CType::TYPE_FLOAT,
+            CType::TYPE_DOUBLE,
+            \defined('\FFI\CType::TYPE_LONGDOUBLE') ? CType::TYPE_LONGDOUBLE : -1,
+            CType::TYPE_UINT8,
+            CType::TYPE_SINT8,
+            CType::TYPE_UINT16,
+            CType::TYPE_SINT16,
+            CType::TYPE_UINT32,
+            CType::TYPE_SINT32,
+            CType::TYPE_UINT64,
+            CType::TYPE_SINT64,
+            CType::TYPE_BOOL,
+            CType::TYPE_CHAR,
+            CType::TYPE_ENUM => null !== $data ? [Caster::PREFIX_VIRTUAL.'cdata' => $data->cdata] : [],
+            CType::TYPE_POINTER => self::castFFIPointer($stub, $type, $data),
+            CType::TYPE_STRUCT => self::castFFIStructLike($type, $data),
+            CType::TYPE_FUNC => self::castFFIFunction($stub, $type),
+            default => $args,
+        };
+    }
+
+    private static function castFFIFunction(Stub $stub, CType $type): array
+    {
+        $arguments = [];
+
+        for ($i = 0, $count = $type->getFuncParameterCount(); $i < $count; ++$i) {
+            $param = $type->getFuncParameterType($i);
+
+            $arguments[] = $param->getName();
+        }
+
+        $abi = match ($type->getFuncABI()) {
+            CType::ABI_DEFAULT,
+            CType::ABI_CDECL => '[cdecl]',
+            CType::ABI_FASTCALL => '[fastcall]',
+            CType::ABI_THISCALL => '[thiscall]',
+            CType::ABI_STDCALL => '[stdcall]',
+            CType::ABI_PASCAL => '[pascal]',
+            CType::ABI_REGISTER => '[register]',
+            CType::ABI_MS => '[ms]',
+            CType::ABI_SYSV => '[sysv]',
+            CType::ABI_VECTORCALL => '[vectorcall]',
+            default => '[unknown abi]'
+        };
+
+        $returnType = $type->getFuncReturnType();
+
+        $stub->class = $abi.' callable('.implode(', ', $arguments).'): '
+            .$returnType->getName();
+
+        return [Caster::PREFIX_VIRTUAL.'returnType' => $returnType];
+    }
+
+    private static function castFFIPointer(Stub $stub, CType $type, CData $data = null): array
+    {
+        $ptr = $type->getPointerType();
+
+        if (null === $data) {
+            return [Caster::PREFIX_VIRTUAL.'0' => $ptr];
+        }
+
+        return match ($ptr->getKind()) {
+            CType::TYPE_CHAR => [Caster::PREFIX_VIRTUAL.'cdata' => self::castFFIStringValue($data)],
+            CType::TYPE_FUNC => self::castFFIFunction($stub, $ptr),
+            default => [Caster::PREFIX_VIRTUAL.'cdata' => $data[0]],
+        };
+    }
+
+    private static function castFFIStringValue(CData $data): string|CutStub
+    {
+        $result = [];
+
+        for ($i = 0; $i < self::MAX_STRING_LENGTH; ++$i) {
+            $result[$i] = $data[$i];
+
+            if ("\0" === $result[$i]) {
+                return implode('', $result);
+            }
+        }
+
+        $string = implode('', $result);
+        $stub = new CutStub($string);
+        $stub->cut = -1;
+        $stub->value = $string;
+
+        return $stub;
+    }
+
+    private static function castFFIStructLike(CType $type, CData $data = null): array
+    {
+        $isUnion = ($type->getAttributes() & CType::ATTR_UNION) === CType::ATTR_UNION;
+
+        $result = [];
+
+        foreach ($type->getStructFieldNames() as $name) {
+            $field = $type->getStructFieldType($name);
+
+            // Retrieving the value of a field from a union containing
+            // a pointer is not a safe operation, because may contain
+            // incorrect data.
+            $isUnsafe = $isUnion && CType::TYPE_POINTER === $field->getKind();
+
+            if ($isUnsafe) {
+                $result[Caster::PREFIX_VIRTUAL.$name.'?'] = $field;
+            } elseif (null === $data) {
+                $result[Caster::PREFIX_VIRTUAL.$name] = $field;
+            } else {
+                $fieldName = $data->{$name} instanceof CData ? '' : $field->getName().' ';
+                $result[Caster::PREFIX_VIRTUAL.$fieldName.$name] = $data->{$name};
+            }
+        }
+
+        return $result;
+    }
+}

Cloner/AbstractCloner.php

@@ -187,6 +187,9 @@ abstract class AbstractCloner implements ClonerInterface
         'RdKafka\Topic' => ['Symfony\Component\VarDumper\Caster\RdKafkaCaster', 'castTopic'],
         'RdKafka\TopicPartition' => ['Symfony\Component\VarDumper\Caster\RdKafkaCaster', 'castTopicPartition'],
         'RdKafka\TopicConf' => ['Symfony\Component\VarDumper\Caster\RdKafkaCaster', 'castTopicConf'],
+
+        'FFI\CData' => ['Symfony\Component\VarDumper\Caster\FFICaster', 'castCTypeOrCData'],
+        'FFI\CType' => ['Symfony\Component\VarDumper\Caster\FFICaster', 'castCTypeOrCData'],
     ];
 
     protected $maxItems = 2500;