source: downloads/boost_1_34_1/tools/build/v2/build-system.jam @ 45

# Copyright 2003, 2005 Dave Abrahams 
# Copyright 2006 Rene Rivera 
# Copyright 2003, 2004, 2005, 2006 Vladimir Prus 
# 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) 

# 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 virtual-target ;
import "class" : new ;
import toolset ;
import regex ;

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 argv = [ modules.peek : ARGV ] ;

local test-config = [ GLOB [ os.environ BOOST_BUILD_PATH ] : test-config.jam ] ;

local debug-config = [ MATCH ^(--debug-configuration)$ : [ modules.peek : ARGV ] ] ;

if $(test-config)
{
    if $(debug-config)
    {
        ECHO "notice: loading test-config.jam from" 
          [ NORMALIZE_PATH $(test-config[1]) ] ;
        ECHO "notice: user-config.jam and site-config.jam will be ignored" ;
    }        
       
    module test-config 
    {
        import toolset : 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 ] ;
    
# Unless ignore-config is set, load the configuration file in
# $(path)/$(basename).jam
local rule load-config ( basename : path + )
{       
    if ! $(ignore-config)    
    {
        if $(debug-config)
        {
            ECHO notice: searching \"$(path)\" for \"$(basename).jam\" ;
            local where = [ GLOB $(path) : $(basename).jam ] ;
            if $(where)
            {            
                ECHO notice: loading $(basename).jam from
                  [ NORMALIZE_PATH $(where[1]) ] ;
            }        
        }        

        modules.load $(basename) : : $(path) ;
        project.load-used-projects $(basename) ;
    }
}

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

local site-path = /etc $(user-path) ; 

if [ os.name ] in NT CYGWIN
{    
    site-path = [ modules.peek : SystemRoot ] $(user-path) ;   
}

load-config site-config : $(site-path) ;

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

local user-config-path = [ MATCH ^--user-config=(.*) : $(argv) ] ;

if $(user-config-path)
{
    if $(debug-config)
    {
        ECHO "Loading explicitly specifier user configuration file:" ;
        ECHO "    $(user-config-path)" ;
    }
    
    
    modules.load user-config : $(user-config-path:BS) : $(user-config-path:D) ;
    project.load-used-projects user-config ;
}
else
{    
    load-config user-config : $(user-path) ;
}


#
# Autoconfigure toolsets based on any instances of --toolset=xx,yy,...zz or
# toolset=xx,yy,...zz in the command line
#
local option-toolsets = [ regex.split-list [ MATCH ^--toolset=(.*) : $(argv) ] : "," ] ;
local feature-toolsets = [ regex.split-list [ MATCH ^toolset=(.*) : $(argv) ] : "," ] ;

# if the user specified --toolset=..., we need to add toolset=... to
# the build request
local extra-build-request ; 

if ! $(ignore-config)
{
    for local t in $(option-toolsets) $(feature-toolsets)
    {
        # Parse toolset-version/properties
        local (t-v,t,v) = [ MATCH (([^-/]+)-?([^/]+)?)/?.* : $(t) ] ;
        local toolset-version = $((t-v,t,v)[1]) ;
        local toolset = $((t-v,t,v)[2]) ;
        local version = $((t-v,t,v)[3]) ;

        if $(debug-config)
        {
            ECHO notice: [cmdline-cfg] Detected command-line request for 
              $(toolset-version): toolset= \"$(toolset)\" "version= \""$(version)\" ;
        }

        local known ;

        # if the toolset isn't known, configure it now.
        if $(toolset) in [ feature.values <toolset>  ]
        {
            known = true ;
        }

        if $(known) && $(version) 
          && ! [ feature.is-subvalue toolset : $(toolset) : version : $(version) ]
        {
            known = ;
        }

        if ! $(known)
        {
            if $(debug-config)
            {
                ECHO notice: [cmdline-cfg] toolset $(toolset-version) 
                  not previously configured; configuring now ; 
            }
            toolset.using $(toolset) : $(version) ;
        }
        else
        {
            if $(debug-config)
            {
                ECHO notice: [cmdline-cfg] toolset $(toolset-version) already configured ;
            }
        }

        # make sure we get an appropriate property into the build request in
        # case the user used the "--toolset=..." form
        if ! $(t) in $(argv)
            && ! $(t) in $(feature-toolsets) 
        {
            if $(debug-config)
            {
                ECHO notice: [cmdline-cfg] adding toolset=$(t) "to build request." ;
            }
            extra-build-request += toolset=$(t) ;
        }
    }
}
    
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> ] 
{
    local default-toolset = gcc ;
    if [ os.name ] = NT
    {
        default-toolset = msvc ;
    }
    
    ECHO "warning: No toolsets are configured." ;
    ECHO "warning: Configuring default toolset" \"$(default-toolset)\". ;
    ECHO "warning: If the default is wrong, you may not be able to build C++ programs." ;
    ECHO "warning: Use the \"--toolset=xxxxx\" option to override our guess." ;
    ECHO "warning: For more configuration options, please consult" ;
    ECHO "warning: http://boost.org/boost-build2/doc/html/bbv2/advanced/configuration.html" ;

    
    if ! $(ignore-config)
    {
        toolset.using $(default-toolset) ;
    }
}

build-request = [ 
  build-request.from-command-line [ 
    modules.peek : ARGV 
  ] $(extra-build-request) 
] ;

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) ;    
}
else
{
    expanded = [ property-set.empty ] ;
}



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


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

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 = ;

# Virtual targets obtained when building main targets references on
# the command line. When running
#
#   bjam --clean main_target
#
# we want to clean the files that belong only to that main target,
# so we need to record which targets are produced.
local results-of-main-targets ;

for local p in $(expanded)
{
    for local t in $(targets)
    {   
        local g = [ $(t).generate $(p) ] ;
        if ! [ class.is-a $(t) : project-target ]
        {
            results-of-main-targets += $(g[2-]) ;
        }        
        virtual-targets += $(g[2-]) ;
    }        
}

# The cleaning is tricky. Say, if
# user says: 
#
#    bjam --clean foo
#
# where 'foo' is a directory, then we want to clean targets
# which are in 'foo' or in any children Jamfiles, but not in any
# unrelated Jamfiles. So, we collect the list of project under which
# cleaning is allowed.
#

local projects-to-clean ;
local targets-to-clean ;
if $(clean) || $(clean-all)
{    
    for local t in $(targets)
    {
        if [ class.is-a $(t) : project-target ]
        {
            projects-to-clean += [ $(t).project-module ] ;
        }       
    }
    
    local subvariants ;
    for local t in $(results-of-main-targets)
    {
        # Don't include roots or sources.
        targets-to-clean += [ virtual-target.traverse $(t) ] ;
    }
    targets-to-clean = [ sequence.unique $(targets-to-clean) ] ;        
}

# Returns 'true' if 'project' is a child of 'current-project',
# possibly indirect, or is equal to 'project'.
# Returns 'false' otherwise.
rule is-child ( project )
{
    if ! $(.is-child.$(project))
    {
        local r = false ;
        if $(project) in $(projects-to-clean)
        {            
            r = true ;
        }
        else 
        {
            local parent = [ project.attribute $(project) parent-module ] ;
            if $(parent) && $(parent) != user-config
            {
                r = [ is-child $(parent) ] ;
            }            
        }       
        
        .is-child.$(project) = $(r) ;
    }
    
    return $(.is-child.$(project)) ;    
}




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

if $(bjam-targets)
{
    UPDATE $(bjam-targets:G=e) ;        
}
else if $(cleanall)
{    
    UPDATE clean-all ;
}
else if $(clean)
{
    local to-clean ;
    for local t in [ virtual-target.all-targets ]
    {
        local p = [ $(t).project ] ;

        # Remove only derived targets.
        if [ $(t).action ]
        {                    
            if $(t) in $(targets-to-clean)
              || [ is-child [ $(p).project-module ] ] = true
              {
                  to-clean += $(t) ;
              }        
        }        
    }
    local to-clean-actual ;
    for local t in $(to-clean)
    {
        to-clean-actual += [ $(t).actualize ] ;
    }
    common.Clean clean : $(to-clean-actual) ;
    UPDATE clean ;
    
    
}

else
{
    UPDATE all ;
}