php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login
Bug #77828 SplFileObject::seek problems on custom stream wrappers
Submitted: 2019-03-31 22:32 UTC Modified: 2019-04-01 08:36 UTC
From: alexey dot khokhryakov at gmail dot com Assigned:
Status: Open Package: SPL related
PHP Version: 7.2.16 OS:
Private report: No CVE-ID: None
View Add Comment Developer Edit
Welcome! If you don't have a Git account, you can't do anything here.
You can add a comment by following this link or if you reported this bug, you can edit this bug over here.
(description)
Block user comment
Status: Assign to:
Package:
Bug Type:
Summary:
From: alexey dot khokhryakov at gmail dot com
New email:
PHP Version: OS:

 

 [2019-03-31 22:32 UTC] alexey dot khokhryakov at gmail dot com
Description:
------------
SplFileObject::seek() works wrong for custom stream wrappers. It should work exactly the same as for native files.

In my example I created simple stream wrapper which just proxies all calls to native fopen/fread/ftell/feof/fseek/stat functions which demonstrates the problem.

Test script:
---------------
<?php
file_put_contents($tmpFilename = tempnam(sys_get_temp_dir(), 'test'), "one line\r\n");
stream_wrapper_register('foo', FooStreamWrapper::class);

foreach ([$tmpFilename, "foo:/{$tmpFilename}"] as $filename) {
    $file = new SplFileObject($filename, 'r');
    $file->seek($file->getSize());
    var_dump($file->key());
}

class FooStreamWrapper {
    private $r;
    public function stream_open($path, $mode) { $this->r = fopen(str_replace('foo:/', '', $path), $mode); return true; }
    public function stream_read($count) { return fread($this->r, $count); }
    public function stream_tell() { return ftell($this->r); }
    public function stream_eof() { return feof($this->r); }
    public function stream_seek($offset, $whence) { return fseek($this->r, $offset, $whence) === 0; }
    public function url_stat($path) { return stat(str_replace('foo:/', '', $path)); }
}


Expected result:
----------------
int(1)
int(1)


Actual result:
--------------
int(1)
int(0)


Patches

Add a Patch

Pull Requests

Add a Pull Request

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2019-03-31 23:19 UTC] requinix@php.net
It's not SplFileObject but your stream wrapper. PHP's file wrapper is reading lines, yours is reading bytes. If you edit yours to read lines as well
  public function stream_read($count) { return fgets($this->r, $count); }
then it works as expected.

Not sure the best way to fix this.
 [2019-04-01 07:38 UTC] alexey dot khokhryakov at gmail dot com
requinix@php.net, I don't think so.

If wrapper::stream_read() proxies calls to fgets() then SplFileObject::fread($count) becomes inconsistent because PHP's file wrapper returns $count of data including linebreaks.
 [2019-04-01 08:12 UTC] requinix@php.net
Try the change I said, see what happens.
 [2019-04-01 08:21 UTC] alexey dot khokhryakov at gmail dot com
I tried and I see that my test script works but it breaks SplFileObject::fread() functionality as I said.

file_put_contents($tmpFilename = tempnam(sys_get_temp_dir(), 'test'), "one\r\ntwo\r\n");
stream_wrapper_register('foo', FooStreamWrapper::class);
$file = new SplFileObject("foo:/{$tmpFilename}", 'r');
var_dump($file->fread($file->getSize()));

Expected:
string(10) "one
two
"

Actual:
string(5) "one
"
 [2019-04-01 08:36 UTC] requinix@php.net
I know it's not correct. I'm saying, you can see the line reading/byte reading behavior if you switch the stream to read lines. There is a bug here.
 
PHP Copyright © 2001-2019 The PHP Group
All rights reserved.
Last updated: Sat Sep 21 01:01:26 2019 UTC