[MPlayer-dev-eng] run command patch

[Reimar Döffinger]

On Wed, Feb 22, 2012 at 09:02:34PM +0100, Reimar Döffinger wrote:
> On Wed, Feb 22, 2012 at 08:42:34PM +0100, Diego Biurrun wrote:
> > On Wed, Feb 22, 2012 at 05:56:21PM +0100, Reimar Döffinger wrote:
> > > On Tue, Feb 21, 2012 at 11:06:00PM +0100, Diego Biurrun wrote:
> > > > On Wed, Feb 15, 2012 at 08:31:09PM +0100, Reimar Döffinger wrote:
> > > > > On Wed, Feb 15, 2012 at 08:16:52PM +0100, Jan Christoph Uhde wrote:
> > > > > > --- DOCS/tech/slave.txt	(revision 34728)
> > > > > > +++ DOCS/tech/slave.txt	(working copy)
> > > > > > @@ -508,11 +508,21 @@
> > > > > >  
> > > > > > -run <value>
> > > > > > -    Run <value> as shell command. In OSD menu console mode stdout and stdin
> > > > > > -    are through the video output driver.
> > > > > > +run <string>
> > > > > > +    Run <string> with expanded variables as shell command. In OSD menu
> > > > > > +    console mode stdout and stdin are through the video output driver.
> > > > > >  
> > > > > > +    Example:
> > > > > > +    <KEY> run "echo '${filename} ${stream_pos}' >> <path_to_file>"
> > > > > >  
> > > > > > +    A POSIX shell would not be able to expand the variables between
> > > > > > +    single quotes. So it should be obvious that ${<var_name>} strings are
> > > > > > +    not shell variables. The syntax with curly braces for shell variables
> > > > > > +    can not be used. Because the variable is either expanded to one
> > > > > > +    of MPlayer's properties or a string of length zero before the
> > > > > > +    command is passed to /bin/sh.
> > > > > 
> > > > > Ah.
> > > > > Maybe more clear:
> > > > > Note: MPlayer will do variable expansion on anything of the form
> > > > > ${somevar} before it is passed to the shell.
> > > > > This means that you cannot use this syntax for anything you actually
> > > > > want the shell to handle.
> > > > > Anything else will be passed on to the shell unchanged, so you can
> > > > > use e.g. $somevar to have the shell expand it instead of MPlayer.
> > > > 
> > > > But what does MPlayer expand?
> > > 
> > > What do you mean? The first sentence says "anything of the form
> > > ${somevar}".
> > > Or do you mean what it expands it to?
> > 
> > I would guess that ${non_existing_var} is expanded to nothing, what is
> > expanded to some sensible value?  I don't remember us having this
> > documented anywhere...
> 
> Everything documented as gettable property in that file should work.
> I am not completely 100% sure about non-existing ones, but I hope
> they will expand to nothing.

On second thought, that might not be true.
E.g. "metadata" might not work.
In which case the property list probably needs an extra column,
"printable".
Everything that supports MP_PROPERTY_PRINT at least should
be fine though.