# Copyright 2003 Dave Abrahams
# Copyright 2003, 2005, 2006 Rene Rivera
# Copyright 2003, 2005, 2006 Vladimir Prus
# Distributed under the Boost Software License, Version 1.0.
# (See accompanying file LICENSE.txt or copy at
# https://www.bfgroup.xyz/b2/LICENSE.txt)

# First of all, check the jam version.
if $(JAM_VERSION:J="") < 030112
{
    ECHO "error: Boost.Jam version 3.1.12 or later required" ;
    EXIT ;
}

local required-rules = GLOB-RECURSIVELY HAS_NATIVE_RULE ;
for local r in $(required-rules)
{
    if ! $(r) in [ RULENAMES ]
    {
        ECHO "error: builtin rule '$(r)' is not present" ;
        ECHO "error: your version of bjam is likely out of date" ;
        ECHO "error: please get a fresh version from SVN." ;
        EXIT ;
    }
}

local native = regex transform 2 ;
while $(native)
{
    if ! [ HAS_NATIVE_RULE $(native[1]) : $(native[2]) : $(native[3]) ]
    {
        ECHO "error: missing native rule '$(native[1]).$(native[2])'" ;
        ECHO "error: or interface version of that rule is too low" ;
        ECHO "error: your version of bjam is likely out of date" ;
        ECHO "error: please get a fresh version from SVN." ;
        EXIT ;
    }
    native = $(native[4-]) ;
}


# Check that the builtin .ENVIRON module is present. We do not have a builtin to
# check that a module is present, so we assume that the PATH environment
# variable is always set and verify that the .ENVIRON module has a non-empty
# value of that variable.
module .ENVIRON
{
    local p = $(PATH) $(Path) $(path) ;
    if ! $(p)
    {
        ECHO "error: no builtin module .ENVIRON is found" ;
        ECHO "error: your version of bjam is likely out of date" ;
        ECHO "error: please get a fresh version from SVN." ;
        EXIT ;
    }
}

# Check that @() functionality is present. Similarly to modules, we do not have
# a way to test this directly. Instead we check that $(TMPNAME) functionality is
# present which was added at roughly the same time (more precisely, it was added
# just before).
{
    if ! $(TMPNAME)
    {
        ECHO "error: no @() functionality found" ;
        ECHO "error: your version of b2 is likely out of date" ;
        ECHO "error: please get a fresh version from SVN." ;
        EXIT ;
    }
}

# Make sure that \n escape is available.
if "\n" = "n"
{
    if $(OS) = CYGWIN
    {
        ECHO "warning: escape sequences are not supported" ;
        ECHO "warning: this will cause major misbehaviour on cygwin" ;
        ECHO "warning: your version of b2 is likely out of date" ;
        ECHO "warning: please get a fresh version from SVN." ;
    }
}


# Bootstrap the module system. Then bring the import rule into the global module.
#
SEARCH on <module@>modules.jam = $(.bootstrap-file:D) ;
module modules { include <module@>modules.jam ; }
IMPORT modules : import : : import ;

{
    # Add module subdirectories to the BOOST_BUILD_PATH, which allows us to make
    # incremental refactoring steps by moving modules to appropriate
    # subdirectories, thereby achieving some physical separation of different
    # layers without changing all of our code to specify subdirectories in
    # import statements or use an extra level of qualification on imported
    # names.

    local subdirs =
        kernel        # only the most-intrinsic modules: modules, errors
        util          # low-level substrate: string/number handling, etc.
        build         # essential elements of the build system architecture
        tools         # toolsets for handling specific build jobs and targets.
        contrib       # user contributed (unreviewed) modules
        .             # build-system.jam lives here
        ;
    local whereami = [ NORMALIZE_PATH $(.bootstrap-file:DT) ] ;
    BOOST_BUILD_PATH += $(whereami:D)/$(subdirs) ;

    modules.poke .ENVIRON : BOOST_BUILD_PATH : $(BOOST_BUILD_PATH) ;
}

# Reload the modules, to clean up things. The modules module can tolerate being
# imported twice.
#
import modules ;

# Process option plugins first to allow them to prevent loading the rest of the
# build system.
#
import option ;
local dont-build = [ option.process ] ;

# Should we skip building, i.e. loading the build system, according to the
# options processed?
#
if ! $(dont-build)
{
    # Allow users to override the build system file from the command-line
    # (mostly for testing).
    local build-system = [ MATCH --build-system=(.*) : $(ARGV) ] ;
    build-system ?= build-system ;

    # Use last element in case of multiple command-line options.
    import $(build-system[-1]) ;
}