[Libguestfs] [PATCH] ./run: Use 'prepend' function to build paths.

[Richard W.M. Jones]

On Fri, Feb 13, 2015 at 11:35:15AM +0100, Pino Toscano wrote:
> On Friday 13 February 2015 10:16:34 Richard W.M. Jones wrote:
> > Add a bash function 'prepend' for intelligently prepending elements to
> > paths.  eg:
> > 
> >   prepend PYTHONPATH "/foo"
> > 
> > would set PYTHONPATH to "/foo" or "/foo:<previous-contents-of-PYTHONPATH>"
> > 
> > Tested by:
> > 
> > (1) Building and testing libguestfs twice: first without libguestfs
> > installed as a system library, and then with it installed.
> > 
> > (2) Examining the output of './run printenv' by hand and comparing
> > environment variables to the expected values.
> > ---
> 
> Nice idea, thanks for it.
> 
> >  # Set LD_LIBRARY_PATH and DYLD_LIBRARY_PATH to contain library.
> > -build_libs_path="$b/src/.libs:$b/java/.libs:$b/gobject/.libs"
> > -export LD_LIBRARY_PATH="$build_libs_path${LD_LIBRARY_PATH:+:}$LD_LIBRARY_PATH"
> > -export DYLD_LIBRARY_PATH="$build_libs_path${DYLD_LIBRARY_PATH:+:}$DYLD_LIBRARY_PATH"
> > +prepend LD_LIBRARY_PATH "$b/gobject/.libs"
> > +prepend LD_LIBRARY_PATH "$b/java/.libs"
> > +prepend LD_LIBRARY_PATH "$b/src/.libs"
> > +prepend DYLD_LIBRARY_PATH "$b/gobject/.libs"
> > +prepend DYLD_LIBRARY_PATH "$b/java/.libs"
> > +prepend DYLD_LIBRARY_PATH "$b/src/.libs"
> > +export LD_LIBRARY_PATH
> > +export DYLD_LIBRARY_PATH
> 
> I'd still leave the build_libs_path variable, so we don't duplicate
> its content twice.

I considered that, but think this way is clearer, even if there's some
minimal duplication.

> >  # virt-p2v-make-* data directory.
> >  if [ -z "$VIRT_P2V_DATA_DIR" ]; then
> > -    VIRT_P2V_DATA_DIR="$b/p2v"
> > +    prepend VIRT_P2V_DATA_DIR "$b/p2v"
> >      export VIRT_P2V_DATA_DIR
> >  fi
> 
> Is prepend needed here? After all, it is just a single directory.

No it's not -- I removed this hunk.

> >  # For Lua.
> >  export LUA=@LUA@
> > +# Can't use 'prepend' here because Lua paths use semicolons.
> >  if [ -z "$LUA_CPATH" ]; then
> >      LUA_CPATH="$b/lua/?.so"
> >  else
> 
> I guess using a second helper like:
> 
>   prepend_semicolon()
>   {
>     eval $1="$2\${$1:+;\$$1}"
>   }
> 
> could help?

Actually what's needed is a more general function which could use a
generic separator and also handle appending, thus coping with:

if [ -z "$CGO_CFLAGS" ]; then
    CGO_CFLAGS="-I$s/src"
else
    CGO_CFLAGS="$CGO_CFLAGS -I$s/src"
fi

Anyway, I have pushed this for now, without the P2V data dir hunk.

Thanks,

Rich.

-- 
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