build/new/toolset.jam

#  Copyright (C) Vladimir Prus 2002. 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.

#  Support for toolset definition.

import feature ;
import numbers ;
import errors : error ;
import property ;

.flag-no = 1 ;

# Initializes an additional toolset-like module.
# First load 'toolset-module' and then calls it's 'init'
# rule with trailing arguments
rule using ( toolset-module : * )
{
    import $(toolset-module) ;
    $(toolset-module).init $(2) : $(3) : $(4) : $(5) : $(6) : $(7) : $(8) : $(9) ;
}

# Expands subfeatures in each property sets.
# e.g
# <toolset>gcc-3.2
# will be converted to
# <toolset>gcc/<toolset-version>3.2
local rule normalize-condition ( property-sets * )
{
    local result ;
    for local p in $(property-sets)
    {
        local split = [ feature.split $(p) ] ;
        local expanded = [ feature.expand-subfeatures [ feature.split $(p) ] ] ;
        result += $(expanded:J=/) ;
    }
    return $(result) ;
}


# Specifies the flags (variables) that must be set on targets under certain
# conditions, described by arguments.
rule flags ( rule-or-module   # If contains dot, should be a rule name.
                              # The flags will be applied when that rule is
                              # used to set up build actions.
                              #
                              # If does not contain dot, should be a module name.
                              # The flags will be applied for all rules in that
                              # module.
    
             variable-name    # Variable that should be set on target
             condition * :    # Can specify either
                              #
                              # - a set of feature names. Values of all mentioned
                              #   feature that are present in build property set
                              #   will be appended to the variable. The 'actualize'
                              #   method will be called on values of all dependency
                              #   features. The next argument will be unused.
                              #
                              # - a set of property sets. If one of those property 
                              #   sets is contained in build properties, 'values'
                              #   will be added to the variable.
                              #   Implied values are not allowed: "<toolset>gcc" should
                              #   be used, not just "gcc". Subfeatures, like in
                              #   "<toolset>gcc-3.2" are allowed.
                              #
                              # - empty. 'values' will be added to the variable 
                              #   unconditionally
             values * )
{
    .$(rule-or-module).flags += $(.flag-no) ;
      
    .$(rule-or-module).variable.$(.flag-no) += $(variable-name) ;
    .$(rule-or-module).values.$(.flag-no) += $(values) ;
    
    if $(condition[1]:G=)
    {
        .$(rule-or-module).match-type.$(.flag-no) += property-set ;
        property.validate-property-sets $(condition) ;
        if ! $(values)
        {
            error empty value set used with property-set match criterion:
              : $(condition) ;
        }
        condition = [ normalize-condition $(condition) ] ;
    }
    else if $(condition)
    {
        .$(rule-or-module).match-type.$(.flag-no) += feature ;
        if $(values)
        {
            error non-empty value set used with feature match criterion ;
        }
    }
    else
    {
        .$(rule-or-module).match-type.$(.flag-no) += unconditional ;
        error empty value set used with unconditional match criterion ;
    }
    
    .$(rule-or-module).condition.$(.flag-no) += $(condition) ;    
    
    .flag-no = [ numbers.increment $(.flag-no) ] ;
}

# Returns the first element of 'property-sets' which is a subset of
# 'properties', or an empty list if no such element exists.
local rule find-property-subset ( property-sets * : properties * )
{
    local result ;
    for local s in $(property-sets)
    {
        if ! $(result)
        {
            if [ feature.split $(s) ] in $(properties)
            {
                result = $(s) ;
            }
        }
    }
    return $(result) ;
}

rule set-target-variables ( rule-or-module target : properties * )
{ 
    for local f in $(.$(rule-or-module).flags) 
    {
        local variable = $(.$(rule-or-module).variable.$(f)) ;
        local condition = $(.$(rule-or-module).condition.$(f)) ;
        local values = $(.$(rule-or-module).values.$(f)) ;
        local result ;
        
        switch $(.$(rule-or-module).match-type.$(f))
        {
         case unconditional :
              result += $(values) ;
              
         case property-set : 
            if [ find-property-subset $(condition) : $(properties) ]
            {
                result += $(values) ;
            }
            
         case feature : # add the values of all specified features to the variable
            local matches = [ property.select $(condition) : $(properties) ] ;
            for local p in $(matches)
            {
                if dependency in [ feature.attributes $(p:G) ]
                {
                    # the value of a dependency feature is a target
                    # and must be actualized
                    result += [ $(p:G=).actualize ] ;
                }
                else
                {
                    result += $(p:G=) ;
                }
            }
        }

        $(variable) on $(target) += $(result) ;
    }
    
    # recurse for any module-specific flags
    local module_ = [ MATCH ^(.+)\\..* : $(rule-or-module) ] ;
    if $(module_)
    {
        set-target-variables $(module_) $(target) : $(properties) ;
    }
}

local rule __test__ ( )
{
    import assert ;
    local p = <c>1 <d>2 <e>3 ;
    assert.result <c>1 <d>2 : find-property-subset <a>0/<b>0/<c>1/<d>2/<e>5 <a>9 : $(p) ;
    assert.result : find-property-subset <a>0/<b>0/<c>9/<d>9/<e>5 <a>9 : $(p) ;
}