Even better emulate POSIX file functions

[Karlson2k]

Properly support feof() and ferror() emulated functions.

[MilhouseVH]

Video playback is still not working in all cases.

Try the sample VIDEO_TS folders here.

The "NOT_OK" folder does not play (testing over SMB) when Karlson2k@e502b09 is included, and it also does not play when this PR is included (in addition to Karlson2k@e502b09).

debug log playing NOT_OK over SMB with a build based on master with PR5694+e502b09. (full log).

[Karlson2k]

Seems that some external lib doesn't handle correctly partial read.
Will test it on Ubuntu.

[MilhouseVH]

I added a debug log to my previous comment in case that is helpful to you.

[Karlson2k]

@MilhouseVH Thanks! Could you do the same with PR5694-e502b09?

[MilhouseVH]

Yes, PR5694-e502b09 is working fine (it's always fine when e502b09 is reverted! :))

debug log playing back NOT_OK over SMB with PR5694-e502b09, and the full log.

[Karlson2k]

@MilhouseVH We always could revert before release. I want to find real root problem. Thanks for testing and log.

[MilhouseVH]

Yes, I think it will be necessary to revert e502b09 unless the root problem can be identified and fixed fairly quickly.

This is a problem for all platforms so reverting e502b09 on master before the next round of betas might be a good idea, then continue testing yourself with e502b09 added (the VIDEO_TS is a reproducible test case for me, at least on Pi/OpenELEC/SMB) until the problem is fixed?

[Karlson2k]

@MilhouseVH Looks like I found the root problem for broken reading.
We are using libdvdread with libdvdcss. In that case all reading comes through dvdcss_read().
At https://github.com/xbmc/xbmc/blob/master/lib/libdvd/libdvdcss/src/libdvdcss.c#L655 patrial read is not supported: pf_read() maps to libc_read() and it simply return read data (libc_read() support for partrial read look fully broken, it use libc_seek() with relative offset while libc_seek() expect absoulte offset).
Without libdvdcss, libdvdnav could use internal file_read() instead of dvdcss_read(). In this case partial reads are correctly supported: https://github.com/xbmc/xbmc/blob/master/lib/libdvd/libdvdread/src/dvd_input.c#L223.
Need to patch libdvdcss.

[Karlson2k]

For fix of broken ifo handling: PR #5700

[topfs2]

Big change very late. I feel a bit reluctant at pulling this.

What bugreports does it fix?

[Karlson2k]

It was supposed to fix reading over SMB, but it didn't fix it as we have a bug in libdvdcss.
Exclude "Correctly support feof() and ferror()" and you'll get obvious changes.

[Karlson2k]

Rebased, only last commit.

[stefansaraev]

ping, is this still needed?

[MartijnKaijser]

If still needed please open a new PR and reference this one.