Re: [PATCH, take 3][cygwin|mingw] Control where win32 DLLs get installed.

[Eric Blake]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

According to Dave Korn on 8/14/2009 5:34 AM:
>   Still finishing it off and getting it tested, but while that's going, here's
> a preview of the path canonicalisation function as I've got it so far; let me
> know if I've done any major no-nos please!

> pathcar="s,^/\([^/]*\).*$,\1,"
> pathcdr="s,^/[^/]*,,"
> removedotparts="s,/\(\.\(/\|$\)\)\+,/,g"
> collapseslashes="s,/\+,/,g"
> 
> # func_normal_abspath path
> # Remove doubled-up and trailing slashes, "." path components,
> # and cancel out any ".." path components in PATH.

Cancelling out .. is wrong for 'symlink/..', when symlink does not
necessarily point to a working directory exactly one level down.  (True,
cygwin does not implement POSIX semantics here, and cancels out foo/..
behind your back rather than properly resolving foo, but this function
will need to work on all other systems that do it correctly).

>   func_normal_abspath_tpath="$1"

Double-quoting not necessary here - variable assignment is already in a
quoted context, and quotes are only needed to protect metacharacters.

>   case "$func_normal_abspath_tpath" in

Likewise - the case argument is already in a double-quoted context.

>     "")
>       # Empty path, that just means $cwd.
>       func_stripname '' '/' "`pwd`"

Can we rely on $PWD instead of forking a process?

>       func_normal_abspath_result="$func_stripname_result"
>       return
>     ;;
>     /*)
>       # Absolute path, do nothing.

Do we want to cater to DOS style absolute paths?  [a-z]:\\

>     ;;
>     *)
>       # Relative path, prepend $cwd.
>       func_normal_abspath_tpath="`pwd`/$func_normal_abspath_tpath"

Again, double quotes aren't necessary.

>     ;;
>   esac
>   # Cancel out all the simple stuff to save iterations.
>   func_normal_abspath_tpath="`$ECHO "$func_normal_abspath_tpath" | $SED \
>         -e "$removedotparts" -e "$collapseslashes"`"

I thought we were trying to move away from $ECHO and instead use the shell
functions.  And you have a portability no-no, documented in the autoconf
manual:

a="`""`"

is non-portable, but can always be replaced by the portable:

a=`""`

See why I don't like spurious "" around variable assignments?

>   # We want the path to end with a slash for ease of parsing, and
>   # doubled-up slashes won't hurt us here, so just add one on.
>   func_normal_abspath_tpath="$func_normal_abspath_tpath/"
>   while :; do
>     func_normal_abspath_tcomponent="`$ECHO "$func_normal_abspath_tpath" | 
> $SED \
>         -e "$pathcar"`"
>     func_normal_abspath_tpath="`$ECHO "$func_normal_abspath_tpath" | $SED \
>         -e "$pathcdr"`"

Nit - I'd break these long lines at |, not after $SED, so that the entire
sed command is on a single line.

>     # Figure out what to do with it
>     case "$func_normal_abspath_tcomponent" in
>       "")
>         # Trailing empty path component, ignore it.
>       ;;
>       ..)
>         # Parent dir; strip last assembled component from result.
>       func_dirname "$func_normal_abspath_result"
>       func_normal_abspath_result="$func_dirname_result"
>       ;;
>       *)
>         # Actual path component, append it.
>         
> func_normal_abspath_result="$func_normal_abspath_result/$func_normal_abspath_tcomponent"
>       ;;
>     esac
>     # Processed it all yet?
>     if test "$func_normal_abspath_tpath" = / ; then
>       # If we ascended to the root using ".." the result may be empty now.
>       if test -z "$func_normal_abspath_result" ; then
>         func_normal_abspath_result=/
>       fi
>       break
>     fi
>   done
> }

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iEYEARECAAYFAkqFV58ACgkQ84KuGfSFAYAGLwCeNF5H7L+noHCwyR6MDPwuFnTk
zJIAoMC0kyZtLZHd9bx4PX4m/J6pcF/O
=y3KX
-----END PGP SIGNATURE-----