# Copyright 2004 Vladimir Prus.
# Copyright 2016 Steven Watanabe
# Distributed under the Boost Software License, Version 1.0.
# (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)

# Provides utility functions for handling cygwin paths

import regex ;

.cygwin-drive-letter-re = ^/cygdrive/([a-z])/(.*) ;

# Like W32_GETREG, except prepend HKEY_CURRENT_USER\SOFTWARE and
# HKEY_LOCAL_MACHINE\SOFTWARE to the first argument, returning the first result
# found. Also accounts for the fact that on 64-bit machines, 32-bit software has
# its own area, under SOFTWARE\Wow6432node.
#
local rule software-registry-value ( path : data ? )
{
    local result ;
    for local root in HKEY_CURRENT_USER HKEY_LOCAL_MACHINE
    {
        for local x64elt in "" Wow6432node\\ # Account for 64-bit windows
        {
            if ! $(result)
            {
                result = [ W32_GETREG $(root)\\SOFTWARE\\$(x64elt)$(path) : $(data) ] ;
            }
        }

    }
    return $(result) ;
}

# :W only works in Cygwin builds of bjam.  This one works on NT builds as well.
#
rule cygwin-to-windows-path ( path )
{
    path = $(path:R="") ; # strip any trailing slash

    local drive-letter = [ SUBST $(path) $(.cygwin-drive-letter-re) $1:/$2 ] ;
    if $(drive-letter)
    {
        path = $(drive-letter) ;
    }
    else if $(path:R=/x) = $(path) # already rooted?
    {
        # Look for a cygwin mount that includes each head sequence in $(path).
        local head = $(path) ;
        local tail = "" ;

        while $(head)
        {
            local root = [ software-registry-value
                "Cygnus Solutions\\Cygwin\\mounts v2\\"$(head) : native ] ;

            if $(root)
            {
                path = $(tail:R=$(root)) ;
                head = ;
            }
            tail = $(tail:R=$(head:D=)) ;

            if $(head) = /
            {
                head = ;
            }
            else
            {
                head = $(head:D) ;
            }
        }
    }
    return [ regex.replace $(path:R="") / \\ ] ;
}