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VarCloner.php
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VarCloner.php
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<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\VarDumper\Cloner;
/**
* @author Nicolas Grekas <p@tchwork.com>
*/
class VarCloner extends AbstractCloner
{
private static $gid;
private static $hashMask = 0;
private static $hashOffset = 0;
private static $arrayCache = [];
/**
* {@inheritdoc}
*/
protected function doClone($var)
{
$len = 1; // Length of $queue
$pos = 0; // Number of cloned items past the minimum depth
$refsCounter = 0; // Hard references counter
$queue = [[$var]]; // This breadth-first queue is the return value
$indexedArrays = []; // Map of queue indexes that hold numerically indexed arrays
$hardRefs = []; // Map of original zval hashes to stub objects
$objRefs = []; // Map of original object handles to their stub object counterpart
$objects = []; // Keep a ref to objects to ensure their handle cannot be reused while cloning
$resRefs = []; // Map of original resource handles to their stub object counterpart
$values = []; // Map of stub objects' hashes to original values
$maxItems = $this->maxItems;
$maxString = $this->maxString;
$minDepth = $this->minDepth;
$currentDepth = 0; // Current tree depth
$currentDepthFinalIndex = 0; // Final $queue index for current tree depth
$minimumDepthReached = 0 === $minDepth; // Becomes true when minimum tree depth has been reached
$cookie = (object) []; // Unique object used to detect hard references
$a = null; // Array cast for nested structures
$stub = null; // Stub capturing the main properties of an original item value
// or null if the original value is used directly
if (\PHP_VERSION_ID >= 70400) {
$cookie = [$cookie];
}
if (!self::$hashMask) {
self::$gid = uniqid(mt_rand(), true); // Unique string used to detect the special $GLOBALS variable
self::initHashMask();
}
$gid = self::$gid;
$hashMask = self::$hashMask;
$hashOffset = self::$hashOffset;
$arrayStub = new Stub();
$arrayStub->type = Stub::TYPE_ARRAY;
$fromObjCast = false;
for ($i = 0; $i < $len; ++$i) {
// Detect when we move on to the next tree depth
if ($i > $currentDepthFinalIndex) {
++$currentDepth;
$currentDepthFinalIndex = $len - 1;
if ($currentDepth >= $minDepth) {
$minimumDepthReached = true;
}
}
$refs = $vals = $queue[$i];
if (\PHP_VERSION_ID < 70200 && empty($indexedArrays[$i])) {
// see https://wiki.php.net/rfc/convert_numeric_keys_in_object_array_casts
foreach ($vals as $k => $v) {
if (\is_int($k)) {
continue;
}
foreach ([$k => true] as $gk => $gv) {
}
if ($gk !== $k) {
$fromObjCast = true;
$refs = $vals = array_values($queue[$i]);
break;
}
}
}
foreach ($vals as $k => $v) {
// $v is the original value or a stub object in case of hard references
if (\PHP_VERSION_ID >= 70400) {
$zvalIsRef = null !== \ReflectionReference::fromArrayElement($vals, $k);
} else {
$refs[$k] = $cookie;
$zvalIsRef = $vals[$k] === $cookie;
}
if ($zvalIsRef) {
$vals[$k] = &$stub; // Break hard references to make $queue completely
unset($stub); // independent from the original structure
if ($v instanceof Stub && isset($hardRefs[spl_object_hash($v)])) {
$vals[$k] = $refs[$k] = $v;
if ($v->value instanceof Stub && (Stub::TYPE_OBJECT === $v->value->type || Stub::TYPE_RESOURCE === $v->value->type)) {
++$v->value->refCount;
}
++$v->refCount;
continue;
}
$refs[$k] = $vals[$k] = new Stub();
$refs[$k]->value = $v;
$h = spl_object_hash($refs[$k]);
$hardRefs[$h] = &$refs[$k];
$values[$h] = $v;
$vals[$k]->handle = ++$refsCounter;
}
// Create $stub when the original value $v can not be used directly
// If $v is a nested structure, put that structure in array $a
switch (true) {
case null === $v:
case \is_bool($v):
case \is_int($v):
case \is_float($v):
continue 2;
case \is_string($v):
if ('' === $v) {
continue 2;
}
if (!preg_match('//u', $v)) {
$stub = new Stub();
$stub->type = Stub::TYPE_STRING;
$stub->class = Stub::STRING_BINARY;
if (0 <= $maxString && 0 < $cut = \strlen($v) - $maxString) {
$stub->cut = $cut;
$stub->value = substr($v, 0, -$cut);
} else {
$stub->value = $v;
}
} elseif (0 <= $maxString && isset($v[1 + ($maxString >> 2)]) && 0 < $cut = mb_strlen($v, 'UTF-8') - $maxString) {
$stub = new Stub();
$stub->type = Stub::TYPE_STRING;
$stub->class = Stub::STRING_UTF8;
$stub->cut = $cut;
$stub->value = mb_substr($v, 0, $maxString, 'UTF-8');
} else {
continue 2;
}
$a = null;
break;
case \is_array($v):
if (!$v) {
continue 2;
}
$stub = $arrayStub;
$stub->class = Stub::ARRAY_INDEXED;
$j = -1;
foreach ($v as $gk => $gv) {
if ($gk !== ++$j) {
$stub->class = Stub::ARRAY_ASSOC;
break;
}
}
$a = $v;
if (Stub::ARRAY_ASSOC === $stub->class) {
// Copies of $GLOBALS have very strange behavior,
// let's detect them with some black magic
$a[$gid] = true;
// Happens with copies of $GLOBALS
if (isset($v[$gid])) {
unset($v[$gid]);
$a = [];
foreach ($v as $gk => &$gv) {
$a[$gk] = &$gv;
}
unset($gv);
} else {
$a = $v;
}
} elseif (\PHP_VERSION_ID < 70200) {
$indexedArrays[$len] = true;
}
break;
case \is_object($v):
case $v instanceof \__PHP_Incomplete_Class:
if (empty($objRefs[$h = $hashMask ^ hexdec(substr(spl_object_hash($v), $hashOffset, \PHP_INT_SIZE))])) {
$stub = new Stub();
$stub->type = Stub::TYPE_OBJECT;
$stub->class = \get_class($v);
$stub->value = $v;
$stub->handle = $h;
$a = $this->castObject($stub, 0 < $i);
if ($v !== $stub->value) {
if (Stub::TYPE_OBJECT !== $stub->type || null === $stub->value) {
break;
}
$h = $hashMask ^ hexdec(substr(spl_object_hash($stub->value), $hashOffset, \PHP_INT_SIZE));
$stub->handle = $h;
}
$stub->value = null;
if (0 <= $maxItems && $maxItems <= $pos && $minimumDepthReached) {
$stub->cut = \count($a);
$a = null;
}
}
if (empty($objRefs[$h])) {
$objRefs[$h] = $stub;
$objects[] = $v;
} else {
$stub = $objRefs[$h];
++$stub->refCount;
$a = null;
}
break;
default: // resource
if (empty($resRefs[$h = (int) $v])) {
$stub = new Stub();
$stub->type = Stub::TYPE_RESOURCE;
if ('Unknown' === $stub->class = @get_resource_type($v)) {
$stub->class = 'Closed';
}
$stub->value = $v;
$stub->handle = $h;
$a = $this->castResource($stub, 0 < $i);
$stub->value = null;
if (0 <= $maxItems && $maxItems <= $pos && $minimumDepthReached) {
$stub->cut = \count($a);
$a = null;
}
}
if (empty($resRefs[$h])) {
$resRefs[$h] = $stub;
} else {
$stub = $resRefs[$h];
++$stub->refCount;
$a = null;
}
break;
}
if ($a) {
if (!$minimumDepthReached || 0 > $maxItems) {
$queue[$len] = $a;
$stub->position = $len++;
} elseif ($pos < $maxItems) {
if ($maxItems < $pos += \count($a)) {
$a = \array_slice($a, 0, $maxItems - $pos);
if ($stub->cut >= 0) {
$stub->cut += $pos - $maxItems;
}
}
$queue[$len] = $a;
$stub->position = $len++;
} elseif ($stub->cut >= 0) {
$stub->cut += \count($a);
$stub->position = 0;
}
}
if ($arrayStub === $stub) {
if ($arrayStub->cut) {
$stub = [$arrayStub->cut, $arrayStub->class => $arrayStub->position];
$arrayStub->cut = 0;
} elseif (isset(self::$arrayCache[$arrayStub->class][$arrayStub->position])) {
$stub = self::$arrayCache[$arrayStub->class][$arrayStub->position];
} else {
self::$arrayCache[$arrayStub->class][$arrayStub->position] = $stub = [$arrayStub->class => $arrayStub->position];
}
}
if ($zvalIsRef) {
$refs[$k]->value = $stub;
} else {
$vals[$k] = $stub;
}
}
if ($fromObjCast) {
$fromObjCast = false;
$refs = $vals;
$vals = [];
$j = -1;
foreach ($queue[$i] as $k => $v) {
foreach ([$k => true] as $gk => $gv) {
}
if ($gk !== $k) {
$vals = (object) $vals;
$vals->{$k} = $refs[++$j];
$vals = (array) $vals;
} else {
$vals[$k] = $refs[++$j];
}
}
}
$queue[$i] = $vals;
}
foreach ($values as $h => $v) {
$hardRefs[$h] = $v;
}
return $queue;
}
private static function initHashMask()
{
$obj = (object) [];
self::$hashOffset = 16 - PHP_INT_SIZE;
self::$hashMask = -1;
if (\defined('HHVM_VERSION')) {
self::$hashOffset += 16;
} else {
// check if we are nested in an output buffering handler to prevent a fatal error with ob_start() below
$obFuncs = ['ob_clean', 'ob_end_clean', 'ob_flush', 'ob_end_flush', 'ob_get_contents', 'ob_get_flush'];
foreach (debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS) as $frame) {
if (isset($frame['function'][0]) && !isset($frame['class']) && 'o' === $frame['function'][0] && \in_array($frame['function'], $obFuncs)) {
$frame['line'] = 0;
break;
}
}
if (!empty($frame['line'])) {
ob_start();
debug_zval_dump($obj);
self::$hashMask = (int) substr(ob_get_clean(), 17);
}
}
self::$hashMask ^= hexdec(substr(spl_object_hash($obj), self::$hashOffset, PHP_INT_SIZE));
}
}