nextcloud/lib/private/largefilehelper.php

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<?php
/**
* Copyright (c) 2014 Andreas Fischer <bantu@owncloud.com>
* This file is licensed under the Affero General Public License version 3 or
* later.
* See the COPYING-README file.
*/
namespace OC;
/**
* Helper class for large files on 32-bit platforms.
*/
class LargeFileHelper {
/**
* pow(2, 53) as a base-10 string.
* @var string
*/
const POW_2_53 = '9007199254740992';
/**
* pow(2, 53) - 1 as a base-10 string.
* @var string
*/
const POW_2_53_MINUS_1 = '9007199254740991';
/**
* @brief Checks whether our assumptions hold on the PHP platform we are on.
*
* @throws \RunTimeException if our assumptions do not hold on the current
* PHP platform.
*/
public function __construct() {
$pow_2_53 = floatval(self::POW_2_53_MINUS_1) + 1.0;
if ($this->formatUnsignedInteger($pow_2_53) !== self::POW_2_53) {
throw new \RunTimeException(
'This class assumes floats to be double precision or "better".'
);
}
}
/**
* @brief Formats a signed integer or float as an unsigned integer base-10
* string. Passed strings will be checked for being base-10.
*
* @param int|float|string $number Number containing unsigned integer data
*
* @throws \UnexpectedValueException if $number is not a float, not an int
* and not a base-10 string.
*
* @return string Unsigned integer base-10 string
*/
public function formatUnsignedInteger($number) {
if (is_float($number)) {
// Undo the effect of the php.ini setting 'precision'.
return number_format($number, 0, '', '');
} else if (is_string($number) && ctype_digit($number)) {
return $number;
} else if (is_int($number)) {
// Interpret signed integer as unsigned integer.
return sprintf('%u', $number);
} else {
throw new \UnexpectedValueException(
'Expected int, float or base-10 string'
);
}
}
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/**
* @brief Tries to get the size of a file via various workarounds that
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* even work for large files on 32-bit platforms.
*
* @param string $filename Path to the file.
*
* @return null|int|float Number of bytes as number (float or int) or
* null on failure.
*/
public function getFileSize($filename) {
$fileSize = $this->getFileSizeViaCurl($filename);
if (!is_null($fileSize)) {
return $fileSize;
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}
$fileSize = $this->getFileSizeViaCOM($filename);
if (!is_null($fileSize)) {
return $fileSize;
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}
$fileSize = $this->getFileSizeViaExec($filename);
if (!is_null($fileSize)) {
return $fileSize;
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}
return $this->getFileSizeNative($filename);
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}
/**
* @brief Tries to get the size of a file via a CURL HEAD request.
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*
* @param string $filename Path to the file.
*
* @return null|int|float Number of bytes as number (float or int) or
* null on failure.
*/
public function getFileSizeViaCurl($filename) {
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if (function_exists('curl_init')) {
$fencoded = urlencode($filename);
$ch = curl_init("file://$fencoded");
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curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, true);
$data = curl_exec($ch);
curl_close($ch);
if ($data !== false) {
$matches = array();
preg_match('/Content-Length: (\d+)/', $data, $matches);
if (isset($matches[1])) {
return 0 + $matches[1];
}
}
}
return null;
}
/**
* @brief Tries to get the size of a file via the Windows DOM extension.
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*
* @param string $filename Path to the file.
*
* @return null|int|float Number of bytes as number (float or int) or
* null on failure.
*/
public function getFileSizeViaCOM($filename) {
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if (class_exists('COM')) {
$fsobj = new \COM("Scripting.FileSystemObject");
$file = $fsobj->GetFile($filename);
return 0 + $file->Size;
}
return null;
}
/**
* @brief Tries to get the size of a file via an exec() call.
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*
* @param string $filename Path to the file.
*
* @return null|int|float Number of bytes as number (float or int) or
* null on failure.
*/
public function getFileSizeViaExec($filename) {
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if (\OC_Helper::is_function_enabled('exec')) {
$os = strtolower(php_uname('s'));
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$arg = escapeshellarg($filename);
$result = null;
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if (strpos($os, 'linux') !== false) {
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$result = $this->exec("stat -c %s $arg");
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} else if (strpos($os, 'bsd') !== false) {
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$result = $this->exec("stat -f %z $arg");
} else if (strpos($os, 'win') !== false) {
$result = $this->exec("for %F in ($arg) do @echo %~zF");
if (is_null($result)) {
// PowerShell
$result = $this->exec("(Get-Item $arg).length");
}
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}
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return $result;
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}
return null;
}
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/**
* @brief Gets the size of a file via a filesize() call and converts
* negative signed int to positive float. As the result of filesize()
* will wrap around after a file size of 2^32 bytes = 4 GiB, this
* should only be used as a last resort.
*
* @param string $filename Path to the file.
*
* @return int|float Number of bytes as number (float or int).
*/
public function getFileSizeNative($filename) {
$result = filesize($filename);
if ($result < 0) {
// For file sizes between 2 GiB and 4 GiB, filesize() will return a
// negative int, as the PHP data type int is signed. Interpret the
// returned int as an unsigned integer and put it into a float.
return (float) sprintf('%u', $result);
}
return $result;
}
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protected function exec($cmd) {
$result = trim(exec($cmd));
return ctype_digit($result) ? 0 + $result : null;
}
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}