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Diffstat (limited to 'lib/private/largefilehelper.php')
| -rw-r--r-- | lib/private/largefilehelper.php | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/lib/private/largefilehelper.php b/lib/private/largefilehelper.php new file mode 100644 index 00000000000..293e09fe2c9 --- /dev/null +++ b/lib/private/largefilehelper.php @@ -0,0 +1,192 @@ +<?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' + ); + } + } + + /** + * @brief Tries to get the size of a file via various workarounds that + * 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; + } + $fileSize = $this->getFileSizeViaCOM($filename); + if (!is_null($fileSize)) { + return $fileSize; + } + $fileSize = $this->getFileSizeViaExec($filename); + if (!is_null($fileSize)) { + return $fileSize; + } + return $this->getFileSizeNative($filename); + } + + /** + * @brief Tries to get the size of a file via a CURL HEAD request. + * + * @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) { + if (function_exists('curl_init')) { + $ch = curl_init("file://$filename"); + 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. + * + * @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) { + 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. + * + * @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) { + if (\OC_Helper::is_function_enabled('exec')) { + $os = strtolower(php_uname('s')); + $arg = escapeshellarg($filename); + $result = ''; + if (strpos($os, 'linux') !== false) { + $result = $this->exec("stat -c %s $arg"); + } else if (strpos($os, 'bsd') !== false) { + $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"); + } + } + return $result; + } + return null; + } + + /** + * @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 $result; + } + + protected function exec($cmd) { + $result = trim(exec($cmd)); + return ctype_digit($result) ? 0 + $result : null; + } +} |