source: downloads/boost_1_33_1/tools/build/v2/build-system.jam @ 13

#  (C) Copyright David Abrahams 2001-2003. Permission to copy, use,
#  modify, sell and distribute this software is granted provided this
#  copyright notice appears in all copies. This software is provided
#  "as is" without express or implied warranty, and with no claim as
#  to its suitability for any purpose.

# This file is part of Boost.Build version 2.  You can think of it as
# forming the main() routine.  It is invoked by the bootstrapping code
# in bootstrap.jam.
#
# The version of bootstrap.jam invoking this lives in
# tools/build/kernel until BBv1 is retired, so that BBv1 can have its
# bootstrap.jam in this directory.

import project ;
import targets ;
import sequence ;
import modules ;
import feature ;
import property-set ;
import build-request ;
import errors : error ;
import "class" : new ;

import builtin ;
import make ;
import os ;

import version ;

# Returns the location of the build system. The primary use case
# is building Boost, where it's sometimes needed to get location
# of other components (like BoostBook files), and it's convenient
# to use location relatively to Boost.Build path.
rule location ( )
{
    local r = [ modules.binding build-system ] ;
    return $(r:P) ;
}


# Check if we can load 'test-config.jam'. If we can, load it and
# ignore user configs.
local test-config = [ GLOB [ os.environ BOOST_BUILD_PATH ] : test-config.jam ] ;
if $(test-config)
{
    module test-config 
    {
        import project : _using : using ;
    }
    import test-config ;    
}

local ignore-config ;
if $(test-config) || --ignore-config in [ modules.peek : ARGV ] 
{    
    ignore-config = true ;
}

local user-path = [ os.home-directories ] [ os.environ BOOST_BUILD_PATH ] ;
    
# Load site-config.
module site-config 
{
    import project : initialize ;
    initialize site-config ;        
}
    
if ! $(ignore-config)
{   
    local path ; 
    if [ os.name ] in NT CYGWIN
    {    
        path = [ modules.peek : SystemRoot ] $(user-path) ;   
    }
    else
    {
        path = /etc $(user-path) ;
    }
    
    
    if --debug-configuration in [ modules.peek : ARGV ]
    {
        local where = [ GLOB $(path) : site-config.jam ] ;
        if $(where)
        {            
            ECHO "notice: loading site-config.jam from" 
              [ NORMALIZE_PATH $(where[1]) ] ;
        }        
    }        
        
    modules.load site-config : : $(path) ;
}


# Load user-config.
module user-config 
{
    import project : initialize ;
    initialize user-config ;        
}

if ! $(ignore-config)
{    
    if --debug-configuration in [ modules.peek : ARGV ]
    {
        local where = [ GLOB $(user-path) : user-config.jam ] ;
        if $(where)
        {
            ECHO "notice: loading user-config.jam from" 
              [ NORMALIZE_PATH $(where[1]) ] ;
        }        
    }    
        
    modules.load user-config : : $(user-path) ;    

}    


if USER_MODULE in [ RULENAMES ]
{
    USER_MODULE site-config user-config ;
}



if --version in [ modules.peek : ARGV ]
{
    version.print ;
    EXIT ;
}

# We always load project in "." so that 'use-project' directives has
# any chance of been seen. Otherwise, we won't be able to refer to
# subprojects using target ids.
if [ project.find "." : "." ]
{    
    current-project = [ project.target [ project.load "." ] ] ;
}    

if ! [ feature.values <toolset> ] 
{
    ECHO "warning: no toolsets are configured." ;
    ECHO "warning: you won't be able to build C++ programs." ;
    ECHO "warning: please consult the documentation." ;
    ECHO ;
}



build-request = [ build-request.from-command-line [ modules.peek : ARGV ] ] ;

properties = [ $(build-request).get-at 2 ] ;

if $(properties) 
{    
    expanded = [ build-request.expand-no-defaults $(properties) ] ;
    local xexpanded ;
    for local e in $(expanded)
    {
        xexpanded += [ property-set.create [ feature.split $(e) ] ] ;
    }
    expanded = $(xexpanded) ;    
}


local target-ids = [ $(build-request).get-at 1 ] ;
local targets
local clean ;


if "--clean" in [ modules.peek : ARGV ]
{
    clean = true ;
}

local bjam-targets ;

# Given a target it, try to find and return corresponding target.
# This is only invoked when there's no Jamfile in "."
# This code somewhat duplicates code in project-target.find but we can't  reuse
# that code without project-targets instance.
rule find-target ( target-id )
{
    local split = [ MATCH (.*)//(.*) : $(target-id) ] ;        
    
    local pm ;
    if $(split)
    {
        pm = [ project.find $(split[1]) : "." ] ;
    }
    else
    {
        pm = [ project.find $(target-id) : "." ] ;
    }
        
    local result ;    
    if $(pm)
    {
        result = [ project.target $(pm) ] ;
    }
        
    if $(split)
    {
        result = [ $(result).find $(split[2]) ] ;
    }
    
    return $(result) ;
}



if ! $(current-project) 
{
    if ! $(target-ids)
    {        
        ECHO "error: no Jamfile in current directory found, and no target references specified."  ;
        EXIT ;
    }
}


for local id in $(target-ids)
{
    if $(id) = clean
    {
        clean = true ;
    }
    else
    {
        local t ;
        if $(current-project)
        {
            t = [ $(current-project).find $(id) : no-error ] ;
        }
        else
        {
            t = [ find-target $(id) ] ;
        }
        
        if ! $(t)
        {
            ECHO "notice: could not find main target " $(id) ;
            ECHO "notice: assuming it's a name of file to create " ;
            bjam-targets += $(id) ;
        }
        else
        {
            targets += $(t) ;
        }                
    }    
}

if ! $(targets)
{
    targets += [ project.target [ project.module-name "." ] ] ; 
}

virtual-targets = ;

if $(expanded) 
{        
    for local p in $(expanded)
    {
        for local t in $(targets)
        {   
            local g = [ $(t).generate $(p) ] ;
            virtual-targets += $(g[2-]) ;
        }        
    }
}
else
{
    for local t in $(targets)
    {        
        local g = [ $(t).generate [ property-set.empty ] ] ;
        virtual-targets += $(g[2-]) ;
    }    
}


actual-targets = ;
for t in $(virtual-targets)
{
    actual-targets += [ $(t).actualize ] ;
}
NOTFILE all ;
DEPENDS all : $(actual-targets) ;

if $(bjam-targets)
{
    UPDATE $(bjam-targets) ;
}
else if $(clean)
{
    UPDATE clean ;
}
else
{
    UPDATE all ;
}