On win32, open() is a function-like macro. The line of code changed
with this commit accidentally expanded the macro. Prevent this macro
expansion. Not sure why that happened now. Since as far as I remember
system functions can be defined as macros, this affects in theory not
only win32.
Because 1) Lua is terrible, and 2) popen() is terrible. Unfortunately,
since Unix is also terrible, this turned out more complicated than I
hoped. As a consequence and to avoid that this code has to be maintained
forever, add a disclaimer that any function in Lua's utils module can
disappear any time. The complexity seems a bit ridiculous, especially
for a feature so far removed from actual video playback, so if it turns
out that we don't really need this function, it will be dropped again.
The motivation for this commit is the same as with 8e4fa5fc.
Note that there is an "#ifndef __GLIBC__". The GNU people are very
special people and thought it'd be convenient to actually declare
"environ", even though the POSIX people, which are also very special
people, state that no header declares this and that the user has to
declare this manually. Since the GNU people overtook the Unix world with
their very clever "embrace, extend, extinguish" strategy, but not 100%,
and trying to build without _GNU_SOURCE is hopeless; but since there
might be Unix environments which support _GNU_SOURCE features partially,
this means that in practice "environ" will be randomly declared or not
declared by system headers. Also, gcc was written by very clever people
too, and prints a warning if an external variable is declared twice (I
didn't check, but I suppose redeclaring is legal C, and not even the gcc
people are clever enough to only warn against a definitely not legal C
construct, although sometimes they do this), ...and since we at mpv hate
compiler warnings, we seek to silence them all. Adding a configure test
just for a warning seems too radical, so we special-case this against
__GLIBC__, which is hopefully not defined on other libcs, especially not
libcs which don't implement all aspects of _GNU_SOURCE, and redefine
"environ" on systems even if the headers define it already (because they
support _GNU_SOURCE - as I mentioned before, the clever GNU people wrote
software THAT portable that other libcs just gave up and implemented
parts of _GNU_SOURCE, although probably not all), which means that
compiling mpv will print a warning about "environ" being redefined, but
at least this won't happen on my system, so all is fine. However, should
someone complain about this warning, I will force whoever complained
about this warning to read this ENTIRE commit message, and if possible,
will also force them to eat a printed-out copy of the GNU Manifesto, and
if that is not enough, maybe this person could even be forced to
convince the very clever POSIX people of not doing crap like this:
having the user to manually declare somewhat central symbols - but I
doubt it's possible, because the POSIX people are too far gone and only
care about maintaining compatibility with old versions of AIX and HP-UX.
Oh, also, this code contains some subtle and obvious issues, but writing
about this is not fun.
stream provides a read buffer (so even something like stream_read_char()
is very fast). This means the stream reads ahead by a few KBs, and
implies that the internal position (s->pos, which would match e.g. the
file position in stream_file.c), and the external position
(stream_tell()) can be different. stream_tell() shows how these are
related.
When dropping buffers, which happens on byte-level discontinuities with
a bunch of streams (including DVB), we should not change the position as
seen by the demuxer. On the other hand, the internal position is not
really meaningful, since these streams aren't seekable anyway. So just
change the code such that stream_drop_buffers() doesn't change the
demuxer visible position.
I'm hoping that this will fix a few problems with DVB. (Also see
previous commit.)
Might matter when libavformat tries to do tiny seekbacks in an
unseekable stream, and the seekback buffer isn't large enough. In this
case, seeking would fail, and would drop the current buffer. The
seekback would end up dropping future data.
This change probably doesn't have any observable effects. libavformat
normally has its own stream buffer, and demux_mkv.c tries carefully
never to seek back.
Similar as the previous commits.
Most of the code is actually copied from the stream_dvdnav.c code, but
I'd rather prefer to duplicate it, than to entangle them. The latter
would probably result in terrible things in a few years.
Same hack as with stream_dvd.c.
VIDEO_TS.IFO files are now opened via stream_dvdnav.c. Directories
containing a VIDEO_TS.IFO or VIDEO_TS/VIDEO_TS.IFO file are also
opened with it.
This was once central, but now it's almost unused. Only vf_divtc still
uses it for extremely weird and incomprehensible reasons. The use in
stream.c is trivial. Replace these, and remove mpbswap.h.
This mechanism originates from MPlayer's way of dealing with blocking
network, but it's still useful. On opening and closing, mpv waits for
network synchronously, and also some obscure commands and use-cases can
lead to such blocking. In these situations, the stream is asynchronously
forced to stop by "interrupting" it.
The old design interrupting I/O was a bit broken: polling with a
callback, instead of actively interrupting it. Change the direction of
this. There is no callback anymore, and the player calls
mp_cancel_trigger() to force the stream to return.
libavformat (via stream_lavf.c) has the old broken design, and fixing it
would require fixing libavformat, which won't happen so quickly. So we
have to keep that part. But everything above the stream layer is
prepared for a better design, and more sophisticated methods than
mp_cancel_test() could be easily introduced.
There's still one problem: commands are still run in the central
playback loop, which we assume can block on I/O in the worst case.
That's not a problem yet, because we simply mark some commands as being
able to stop playback of the current file ("quit" etc.), so input.c
could abort playback as soon as such a command is queued. But there are
also commands abort playback only conditionally, and the logic for that
is in the playback core and thus "unreachable". For example,
"playlist_next" aborts playback only if there's a next file. We don't
want it to always abort playback.
As a quite ugly hack, abort playback only if at least 2 abort commands
are queued - this pretty much happens only if the core is frozen and
doesn't react to input.
Because that might be a bad idea.
Note that remote playlists still can use any protocol marked with
is_safe and is_network, because the case of http-hosted playlists
containing URLs using other streaming protocols is not unusual.
Until now, you had to use --load-unsafe-playlists or --playlist to get
playlists loaded. Change this and always load playlists by default.
This still attempts to reject unsafe URLs. For example, trying to invoke
libavdevice pseudo-demuxer is explicitly prevented. Local paths and any
http links (and some more) are always allowed.
bstr.c doesn't really deserve its own directory, and compat had just
a few files, most of which may as well be in osdep. There isn't really
any justification for these extra directories, so get rid of them.
The compat/libav.h was empty - just delete it. We changed our approach
to API compatibility, and will likely not need it anymore.
Don't reconnect to the cache (since the cached stream already handles
reconnection). This is necessary, because since commit 0b428e44 the
"streaming" field (which also controls whether attempting to reconnect
makes sense at all) is inherited to the cache stream wrapper.
Also, let the stream reset its own position on reconnect. This removes
some assumptions and messy handling from the reconnect function.
Make sure the cache is dropped on reconnect. This takes care of
readjusting the stream position if necessary. (Also drop the cache on
DVB channel switching commands.)
Add the --cache-secs option, which literally overrides the value of
--demuxer-readahead-secs if the stream cache is active. The default
value is very high (10 seconds), which means it can act as network
cache.
Remove the old behavior of trying to pause once the byte cache runs
low. Instead, do something similar wit the demuxer cache. The nice
thing is that we can guess how many seconds of video it has cached,
and we can make better decisions. But for now, apply a relatively
naive heuristic: if the cache is below 0.5 secs, pause, and wait
until at least 2 secs are available.
Note that due to timestamp reordering, the estimated cached duration
of video might be inaccurate, depending on the file format. If the
file format has DTS, it's easy, otherwise the duration will seemingly
jump back and forth.
DVD and Bluray (and to some extent cdda) require awful hacks all over
the codebase to make them work. The main reason is that they act like
container, but are entirely implemented on the stream layer. The raw
mpeg data resulting from these streams must be "extended" with the
container-like metadata transported via STREAM_CTRLs. The result were
hacks all over demux.c and some higher-level parts.
Add a "disc" pseudo-demuxer, and move all these hacks and special-cases
to it.
For remarks, pretty much see the manpage additions. Could help with
network streams that require too much seeking (maybe), or might be
extended to help with the use case of watching and downloading a file
at the same time.
In general, it might be a useless feature and could be removed again.
While I'm not very fond of "const", it's important for declarations
(it decides whether a symbol is emitted in a read-only or read/write
section). Fix all these cases, so we have writeable global data only
when we really need.
Usually, each stream driver declares the size and option list of its
private data. This was pretty natural for when most streams still used
global variables to setup their defaults. They did by pointing
priv_defaults to the (mutable) struct containing the option values. But
falls short when storing the option values in MPOpts. So provide a
somewhat inelegant but simple way to let the stream implementation setup
the priv struct at initialization time.
This is done with the get_defaults callback. It should return a copy of
the struct used in MPOpts. (A copy, because if MPOpts is changed, string
fields might be deallocated, and if that field is not described by
stream_info.options, it won't be copied on init.)
If a single person complains, I will readd it. But I don't expect that
this will happen.
The main reason for removing this is that it's some of the most unclean
code remaining, it's unmaintained, and I've never ever heard of someone
using it.
So, basically this worked only with streams that were not local files,
because stream_dvd.c "intercepts" local files to check whether they
point to DVD images. This means if a stream is not writeable, we have to
try the next stream implementation.
Unbreaks 2-pass encoding.
For some reason, we support writeable streams. (Only encoding uses that,
and the use of it looks messy enough that I want to replace it with FILE
or avio today.)
It's a chaos: most streams do not actually check the mode parameter like
they should. Simplify it, and let streams signal availability of write
mode by setting a flag in the stream info struct.
Stop using it in most places, and prefer STREAM_CTRL_GET_SIZE. The
advantage is that always the correct size will be used. There can be no
doubt anymore whether the end_pos value is outdated (as it happens often
with files that are being downloaded).
Some streams still use end_pos. They don't change size, and it's easier
to emulate STREAM_CTRL_GET_SIZE using end_pos, instead of adding a
STREAM_CTRL_GET_SIZE implementation to these streams.
Make sure int64_t is always used for STREAM_CTRL_GET_SIZE (it was
uint64_t before).
Remove the seek flags mess, and replace them with a seekable flag. Every
stream must set it consistently now, and an assertion in stream.c checks
this. Don't distinguish between streams that can only be forward or
backwards seeked, since we have no such stream types.
stream.start_pos was needed for optical media only, and (apparently) not
for very good reasons. Just get rid of it.
For stream_dvd, we don't need to do anything. Byte seeking was already
removed from it earlier.
For stream_cdda and stream_vcd, emulate the start_pos by offsetting the
stream pos as seen by the rest of mpv.
The bits in discnav.c and loadfile.c were for dealing with the code
seeking back to the start in demux.c. Handle this differently by
assuming the demuxer is always initialized with the stream at start
position, and instead seek back if initializing the demuxer fails.
Remove the --sb option, which worked by modifying stream.start_pos. If
someone really wants this option, it could be added back by creating a
"slice" stream (actually ffmpeg already has such a thing).
Some options change from percentages to number of kilobytes; there are
no cache options using percentages anymore.
Raise the default values. The cache is now 25000 kilobytes, although if
your connection is slow enough, the maximum is probably never reached.
(Although all the memory will still be used as seekback-cache.)
Remove the separate --audio-file-cache option, and use the cache default
settings for it.
This used global variables for the asynchronous interrupt callback.
Pick the simple and dumb solution and stuff the callback into
mpv_global. Do this because interrupt checking should also work in the
connect phase, and currently stream creation equates connecting.
Ideally, this would be passed to the stream on creation instead, or
connecting would be separated from creation. But since I don't know yet
which is better, and since moving stream/demuxer into their own thread
is something that will happen later, go with the mpv_global solution.
This is the only function which actually used the time argument of
stream_check_interrupt(). Considering that the whole player freezes
anyway, this is not worth the complication.
Also generally reduce the maximum wait time due to timeout. Introduce
exponential backoff, which makes the first reconnect retries faster, but
still waits up to 500ms in the later retries.
This commit introduces new stream protocols: bdnav(and others).
bdnav stream shares lots of codes with original bluray stream, so
it's not separated in different source file.
Major difference from bluray is that bdnav does not support longest
title because there is no way to query that information.
bdnav://menu and bdnav://first correspond to top menu title and
first play title respectively, though they often point same title.
Also, binary position based seeking has been removed, because it
didn't have no point.
This is probably ok. Probing could hit this case very often, since it'll
mean running this function on potentially binary data, but on the other
hand, probing usually uses a memory stream (to limit the amount of data
read), and memory streams have s->log silenced (details see
open_memory_stream()).
This simplifies the implementation and should make it more robust. For
example, we return an error if a line is longer than the provided buffer
(instead of splitting the line).
The code is much shorter, because now finding the new line and reading
characters is done in one go.
Streams like CDDA have special requirements in what quantities data can
be read: you can only read a sector at once, not more and not less. The
stream_peek() function didn't respect that and set less (used internal
buffer size of 2048 bytes, instead of CD sector size of 2352 bytes), so
no data was read and EOF was accidentally set, making playback with
cdda:// fail.
This is a regression since commit 9a723f, but that commit merely exposed
the issue (the redundant seek would clear the EOF flag).
Always pass around mp_log contexts in the option parser code. This of
course affects all users of this API as well.
In stream.c, pass a mp_null_log, because we can't do it properly yet.
This will be fixed later.
Since m_option.h and options.h are extremely often included, a lot of
files have to be changed.
Moving path.c/h to options/ is a bit questionable, but since this is
mainly about access to config files (which are also handled in
options/), it's probably ok.
The tmsg stuff was for the internal gettext() based translation system,
which nobody ever attempted to use and thus was removed. mp_gtext() and
set_osd_tmsg() were also for this.
mp_dbg was once enabled in debug mode only, but since we have log level
for enabling debug messages, it seems utterly useless.
On dvdnav, caching kind of works but not really. (Not our fault, at
least not fully. It's due to libdvdnav being slightly misdesigned; see
previous commit for some explanations.)
The TV code is implemented in the demuxer, and the stream implementation
is just a wrapper, so caching makes no sense here.
There was already something similar in the code that did the actual
seek, but I think seeking to the same position could still trigger an
actual seek due to weid interaction with the buffer.
This readds a more or less completely new dvdnav implementation, though
it's based on the code from before commit 41fbcee. Note that this is
rather basic, and might be broken or not quite usable in many cases.
Most importantly, navigation highlights are not correctly implemented.
This would require changes in the FFmpeg dvdsub decoder (to apply a
different internal CLUT), so supporting it is not really possible right
now. And in fact, I don't think I ever want to support it, because it's
a very small gain for a lot of work. Instead, mpv will display fake
highlights, which are an approximate bounding box around the real
highlights.
Some things like mouse input or switching audio/subtitles stream using
the dvdnav VM are not supported.
Might be quite fragile on transitions: if dvdnav initiates a transition,
and doesn't give us enough mpeg data to initialize video playback, the
player will just quit.
This is added only because some users seem to want it. I don't intend to
make mpv a good DVD player, so the very basic minimum will have to do.
How about you just convert your DVD to proper video files?
pthreads should be available anywhere. Even if not, for environment
without threads a pthread wrapper could be provided that can't actually
start threads, thus disabling features that require threads.
Make pthreads mandatory in order to simplify build dependencies and to
reduce ifdeffery. (Admittedly, there wasn't much complexity, but maybe
we will use pthreads more in the future, and then it'd become a real
bother.)
The configure followed 5 different convetions of defines because the next guy
always wanted to introduce a new better way to uniform it[1]. For an
hypothetic feature 'hurr' you could have had:
* #define HAVE_HURR 1 / #undef HAVE_DURR
* #define HAVE_HURR / #undef HAVE_DURR
* #define CONFIG_HURR 1 / #undef CONFIG_DURR
* #define HAVE_HURR 1 / #define HAVE_DURR 0
* #define CONFIG_HURR 1 / #define CONFIG_DURR 0
All is now uniform and uses:
* #define HAVE_HURR 1
* #define HAVE_DURR 0
We like definining to 0 as opposed to `undef` bcause it can help spot typos
and is very helpful when doing big reorganizations in the code.
[1]: http://xkcd.com/927/ related
Never check s->seek (except in init), because it'd have to check
s->flags anyway. Also, for fast skippable streams (like pipes), don't
set the bit that indicates support for seek forward.
Make sure s->end_pos is always 0 for unseekable streams. Lots of code
outside of stream.c uses this to check seeking support.
By default, libavformat uses UDP for rtsp playback. This doesn't work
very well. Apparently the reason is that the buffer sizes libavformat
chooses for UDP are way too small, and switching to TCP gets rid of this
issue entirely (thanks go to Reimar Döffinger for figuring this out).
In theory, you can set buffer sizes as libavformat options, but that
doesn't seem to help.
Add an option to select the rtsp transport, and make TCP the default.
Also remove an outdated comment from stream.c.
Until now, stream_peek() read only the bare minimum it had to read from
the stream. But this could cause problems, such as being very
inefficient when peeking a lot, or conflicting with ability to seek
back. (The latter issue can be caused by peeking a few bytes, and then
doing a stream_read() with a size that is 1 byte longer: this would read
the peeked data, then call stream_fill_buffer(), which throws away the
previously peeked bytes - so you can't seek back anymore. This is
mitigated by a hack in demux_open(): it peeks a full buffer, to avoid
that peeking/reading during demuxer probing [or before that, in a stream
filter] can cause the buffer to be dropped.)
Apparently, it is popular to store large files in uncompressed rar
archives. Extracting files is not practical, and some media players
suport playing directly from uncompressed rar (at least VLC and some
DirectShow components).
Storing or accessing files this way is completely idiotic, but it is
a common practice, and the ones subjected to this practice can't do
much to change this (at least that's what I assume/hope). Also, it's
a feature request, so we say yes.
This code is mostly taken from VLC (commit f6e7240 from their git tree).
We also copy the way this is done: opening a rar file by itself yields
a playlist, which contains URLs to the actual entries in the rar file.
Compressed entries are simply skipped.
Add a stream filter concept, in which streams can be opened on top of
an underlying "source" stream. Change the open code to make this
easier, and also to account for some mechanisms that will be needed
for this.
The following commit will add stream_rar, which contains such a stream
filter.
This is really not needed. While we really can't take a loaded buffer
over to the cache, there's no reason why the cache couldn't read this
buffer normally.
On the other hand, this code could cause trouble when probing from a
stream before the cache has been enabled.
The way the url_options field was handled was not entirely sane: it's
actually a flexible array member, so it points to garbage for streams
which do not initialize this member (it just points to the data right
after the struct, which is garbage in theory and practice). This was
not actually a problem, since the field is only used if priv_size is
set (due to how this stuff is used). But it doesn't allow setting
priv_size only, which might be useful in some cases.
Also, make the protocols array not a fixed size array. Most stream
implementations have only 1 protocol prefix, but stream_lavf.c has
over 10 (whitelists ffmpeg protocols). The high size of the fixed
size protocol array wastes space, and it is _still_ annoying to
add new prefixes to stream_lavf (have to bump the maximum length),
so make it arbitrary length.
The two changes (plus some more cosmetic changes) arte conflated into
one, because it was annoying going over all the stream implementations.
Modeled after the old playlist_parser.c, but actually new code, and it
works a bit differently.
Demuxers (and sometimes streams) are the component that should be used
to open files and to determine the file format. This was already done
for subtitles, but playlists still use a separate code path.
Instead of always skipping in STREAM_BUFFER_SIZE blocks, allow an
arbitrary size. This allows - in theory - faster forward seeking in
pipes.
(Maybe not a very significant change, but it reduces the number of
things that depend on STREAM_BUFFER_SIZE for no good reason. Though
we still use that value as minimum read size.)
stream_file.c contains some code meant for forward seeking with pipes.
This simply reads data until the seek position is reached. Move this
code to stream.c. This stops stream_file from doing strange things
(messing with stream internals), and removes the code duplication too.
We also make stream_seek_long() use the new skip code. This is shorter
and much easier to follow than the old code, which basically did strange
things.
So for example "file:///file%20name.mkv" will open "file name.mkv".
I'm not sure whether we want/need this. The old code didn't do it.
Also, it's not really clear whether this is handled correctly. It
seems the corresponding freedesktop.org "standard" allows a (useless)
hostname part, which we should skip in theory. The number of slashes
is not really clear either. We can open relative filenames (by removing
one of the slashes from the example above), which is perhaps an
unneeded feature. How does this even work with Windows paths?
This issues can probably be corrected later.
The URL unescape code is based on code from m_option.c removed with
a recent commit.
Move the URL parsing code from m_option.c to stream.c, and simplify it
dramatically. This code originates from times when http code used this,
but now it's just relict from other stream implementations reusing this
code. Remove the unused bits and simplify the rest.
stream_vcd is insane, and the priv struct is different on every
platform, so drop the URL parsing. This means you can't specify a track
anymore, only the device. (Does anyone use stream_vcd? Not like this
couldn't be fixed, but it doesn't seem worth the effort, especially
because it'd require potentially touching platform specific code.)
These were printed only with -v. Most streams had them set to useless
or redundant values, so it's just badly maintained bloat.
Since we remove the "author" field too, and since this may have
copyright implications, we add the contents of the author fields to
the file headers, except if the name is already part of the file header.
Stream implementations could set this to a unix file descriptor. The
generic stream code could use it as fallback for a few things. This
was confusing and insane. In most cases, the stream implementations
defined all callbacks, so setting the fd member didn't have any
advantages, other than avoiding defining a private struct to store it.
It appears that even if the stream implementation used close() on the
fd (or something equivalent), stream.c would close() it a second time
(and on windows, even would call closesocket()), which should be proof
for the insanity of this code.
For stream_file.c, additionally make sure we don't close stdin or
stdout if "-" is used as filename.
For stream_vcd.c, remove the control() code. This code most likely
didn't make the slightest sense, because it used a different type
for stream->priv. It also leaked memory. Maybe it worked, but it's
incorrect and insignificant anyway, so kill it. This code was added
with commit 9521c19 (svn commit 31019).
Untested for all protocols other than stream_file.c.
This removes the dependency on DEMUXER_TYPE_* and the file_format
parameter from the stream open functions.
Remove some of the playlist handling code. It looks like this was
needed only for loading linked mov files with demux_mov (which was
removed long ago).
Delete a minor bit of dead network-related code from stream.c as well.
Add this option, which lets users set the cache size without forcing it
even when playing from the local filesystem.
Also document the default value explicitly.
The Matroska linked segments case is slightly simplified: they can
never come from network (mostly because it'd be insane, and we can't
even list files from network sources), so the cache will never be
enabled automatically.
Commit 7b16d4b changed some stream implementations to check the buffer
size passed to them. This made stream_cdda stop working, because the
default buffer size is smaller than the CDIO frame size. So pass the
sector size instead of the (arbitrary) default buffer size.
Seeking to position 0 meant to try reconnecting with some streams,
actually just the internal http implementation. This has been removed,
so we don't need the special handling anymore.
This means we don't have to be stuck in a retry loop if the stream
doesn't even support reconnect.
This was an old leftover from an earlier cleanup (which happened in
2003), and which used "special" stuff for streams that could be only
forward-seeked.
Also, don't add mode flags to s->flags; they're supposed to be in
s->mode instead.
This was under CONFIG_NETWORKING, so in theory it should have been save
to remove. But actually this disables forward skipping when reading
from a pipe. (Still a questionable feature, because it doesn't behave
well with libavformat - but it was not supposed to be changed.)
This commit removes the "old" networking code in favor of libavformat's
code.
The code was still used for mp_http, udp, ftp, cddb. http has been
mapped to libavformat's http support since approximately 6 months ago.
udp and ftp have support in ffmpeg (though ftp was added only last
month). cddb support is removed with this commit - it's probably not
important and rarely used if at all, so we don't care about it.
When reading something successfully, the eof flag should never be 1, so
clear it in these situations. The eof flag will be set properly on the
next read call.
stream_read_unbuffered() can sometimes return negative values on error.
Change that to return 0 - the negative values are nowhere used anyway.
If distinguishing errors and EOF is really needed, a flag could be added
instead.
This also fixes the stream_read_partial() call in cache.c, which assumes
the return values is always >= 0.
Seems like a completely unnecessary complication. Instead, always add a
1 byte padding (could be extended if a caller needs it), and clear it.
Also add some documentation. There was some, but it was outdated and
incomplete.
This is useless on the cache side. The sector is needed only to deal
with stream implementations which are not byte addressable, and the
cache is always byte addressable.
Also set a default read_chunk value. (This value is never used unless
you chain multiple caches, but it's cleaner.)
This was probably done this way to ensure that after a successful seek,
the reported stream position is the same as the requested seek position.
But it doesn't make too much sense, since both stream->pos and the
stream implementation's internal position will go out of sync.
The stream EOF flag should only be set when trying to read past the end
of the file (relatively similar to unix files). Always clear the EOF
flag on seeking. Trying to set it "properly" (depending whether data is
available at seek destination or not) might be an ok idea, but would
require attention to too many special cases. I suspect before this
commit (and in MPlayer etc. too), the EOF flag wasn't handled
consistently when the stream position was at the end of the file.
Fix one special case in ebml.c and stream_skip(): this function couldn't
distinguish between at-EOF and past-EOF either.
EOF should be set when reading more data fails. The stream
implementations have nothing to say here and should behave correctly
when trying to read when EOF was actually read.
Even when seeking, a correct EOF flag should be guaranteed. stream_seek()
(or actually stream_seek_long()) calls stream_fill_buffer() at least
once, which also updates the EOF flag.
