project.jam

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{
    .current-project = $(.saved-current-project[-1]) ;
    .saved-current-project = $(.saved-current-project[1--2]) ;
}


# Returns the project-attribute instance for the specified Jamfile module.
#
rule attributes ( project )
{
    return $($(project).attributes) ;
}


# Returns the value of the specified attribute in the specified Jamfile module.
#
rule attribute ( project attribute )
{
    return [ $($(project).attributes).get $(attribute) ] ;
}


# Returns the project target corresponding to the 'project-module'.
#
rule target ( project-module )
{
    if ! $(.target.$(project-module))
    {
        .target.$(project-module) = [ new project-target $(project-module)
            : $(project-module)
            : [ attribute $(project-module) requirements ] ] ;
    }
    return $(.target.$(project-module)) ;
}


# Use/load a project.
#
rule use ( id : location )
{
    local saved-project = $(.current-project) ;
    local project-module = [ project.load $(location) ] ;
    local declared-id = [ project.attribute $(project-module) id ] ;

    if ! $(declared-id) || $(declared-id) != $(id)
    {
        # The project at 'location' either has no id or that id is not equal to
        # the 'id' parameter.
        if $($(id).jamfile-module) && ( $($(id).jamfile-module) !=
            $(project-module) )
        {
            errors.user-error Attempt to redeclare already existing project id
                '$(id)' ;
        }
        $(id).jamfile-module = $(project-module) ;
    }
    .current-project = $(saved-project) ;
}


# Defines a Boost.Build extension project. Such extensions usually contain
# library targets and features that can be used by many people. Even though
# extensions are really projects, they can be initialized as a module would be
# with the "using" (project.project-rules.using) mechanism.
#
rule extension ( id : options * : * )
{
    # The caller is a standalone module for the extension.
    local mod = [ CALLER_MODULE ] ;

    # We need to do the rest within the extension module.
    module $(mod)
    {
        import path ;

        # Find the root project.
        local root-project = [ project.current ] ;
        root-project = [ $(root-project).project-module ] ;
        while
            [ project.attribute $(root-project) parent-module ] &&
            [ project.attribute $(root-project) parent-module ] != user-config
        {
            root-project = [ project.attribute $(root-project) parent-module ] ;
        }

        # Create the project data, and bring in the project rules into the
        # module.
        project.initialize $(__name__) : [ path.join [ project.attribute
            $(root-project) location ] ext $(1:L) ] ;

        # Create the project itself, i.e. the attributes. All extensions are
        # created in the "/ext" project space.
        project /ext/$(1) : $(2) : $(3) : $(4) : $(5) : $(6) : $(7) : $(8) :
            $(9) ;
        local attributes = [ project.attributes $(__name__) ] ;

        # Inherit from the root project of whomever is defining us.
        project.inherit-attributes $(__name__) : $(root-project) ;
        $(attributes).set parent-module : $(root-project) : exact ;
    }
}


rule glob-internal ( project : wildcards + : excludes * : rule-name )
{
    local location = [ $(project).get source-location ] ;

    local result ;
    local paths = [ path.$(rule-name) $(location) :
        [ sequence.transform path.make : $(wildcards) ] :
        [ sequence.transform path.make : $(excludes) ] ] ;
    if $(wildcards:D) || $(rule-name) != glob
    {
        # The paths we have found are relative to the current directory, but the
        # names specified in the sources list are assumed to be relative to the
        # source directory of the corresponding project. So, just make the names
        # absolute.
        for local p in $(paths)
        {
            result += [ path.root $(p) [ path.pwd ] ] ;
        }
    }
    else
    {
        # There were no wildcards in the directory path, so the files are all in
        # the source directory of the project. Just drop the directory, instead
        # of making paths absolute.
        result = $(paths:D="") ;
    }

    return $(result) ;
}


# This module defines rules common to all projects.
#
module project-rules
{
    rule using ( toolset-module : * )
    {
        import toolset ;
        import modules ;
        import project ;

        # Temporarily change the search path so the module referred to by
        # 'using' can be placed in the same directory as Jamfile. User will
        # expect the module to be found even though the directory is not in
        # BOOST_BUILD_PATH.
        local x = [ modules.peek : BOOST_BUILD_PATH ] ;
        local caller = [ modules.binding $(__name__) ] ;
        modules.poke : BOOST_BUILD_PATH : $(caller:D) $(x) ;
        toolset.using $(1) : $(2) : $(3) : $(4) : $(5) : $(6) : $(7) : $(8) : $(9) ;
        modules.poke : BOOST_BUILD_PATH : $(x) ;

        # The above might have clobbered .current-project. Restore the correct
        # value.
        modules.poke project : .current-project
            : [ project.target $(__name__) ] ;
    }

    import modules ;

    rule import ( * : * : * )
    {
        modules.import project ;

        local caller = [ CALLER_MODULE ] ;
        local saved = [ modules.peek project : .current-project ] ;
        module $(caller)
        {
            modules.import $(1) : $(2) : $(3) ;
        }
        modules.poke project : .current-project : $(saved) ;
    }

    rule project ( id ? : options * : * )
    {
        import errors ;
        import path ;
        import project ;

        local attributes = [ project.attributes $(__name__) ] ;
        if $(id)
        {
           $(attributes).set id : $(id) ;
        }

        local explicit-build-dir ;

        for n in 2 3 4 5 6 7 8 9
        {
            local option = $($(n)) ;
            if $(option)
            {
                $(attributes).set $(option[1]) : $(option[2-]) ;
            }
            if $(option[1]) = "build-dir"
            {
                explicit-build-dir = [ path.make $(option[2-]) ] ;
            }
        }

        # If '--build-dir' is specified, change the build dir for the project.
        local global-build-dir =
            [ modules.peek project : .global-build-dir ] ;

        if $(global-build-dir)
        {
            local location = [ $(attributes).get location ] ;
            # Project with an empty location is a 'standalone' project such as
            # user-config or qt. It has no build dir. If we try to set build dir
            # for user-config, we shall then try to inherit it, with either
            # weird or wrong consequences.
            if $(location) && $(location) = [ $(attributes).get project-root ]
            {
                # Re-read the project id, since it might have been changed in
                # the project's attributes.
                id = [ $(attributes).get id ] ;
                # This is Jamroot.
                if $(id)
                {
                    if $(explicit-build-dir) &&
                        [ path.is-rooted $(explicit-build-dir) ]
                    {
                        errors.user-error Absolute directory specified via
                            'build-dir' project attribute : Do not know how to
                            combine that with the --build-dir option. ;
                    }
                    # Strip the leading slash from id.
                    local rid = [ MATCH /(.*) : $(id) ] ;
                    local p = [ path.join
                        $(global-build-dir) $(rid) $(explicit-build-dir) ] ;

                    $(attributes).set build-dir : $(p) : exact ;
                }
            }
            else
            {
                # Not Jamroot.
                if $(explicit-build-dir)
                {
                    errors.user-error When --build-dir is specified, the
                        'build-dir' project : attribute is allowed only for
                        top-level 'project' invocations ;
                }
            }
        }
    }

    # Declare and set a project global constant. Project global constants are
    # normal variables but should not be changed. They are applied to every
    # child Jamfile.
    #
    rule constant (
        name  # Variable name of the constant.
        : value +  # Value of the constant.
    )
    {
        import project ;
        local p = [ project.target $(__name__) ] ;
        $(p).add-constant $(name) : $(value) ;
    }

    # Declare and set a project global constant, whose value is a path. The path
    # is adjusted to be relative to the invocation directory. The given value
    # path is taken to be either absolute, or relative to this project root.
    #
    rule path-constant (
        name  # Variable name of the constant.
        : value +  # Value of the constant.
        )
    {
        import project ;
        local p = [ project.target $(__name__) ] ;
        $(p).add-constant $(name) : $(value) : path ;
    }

    rule use-project ( id : where )
    {
        # See comment in 'load' for explanation.
        .used-projects += $(id) $(where) ;
    }

    rule build-project ( dir )
    {
        import project ;
        local attributes = [ project.attributes $(__name__) ] ;

        local now = [ $(attributes).get projects-to-build ] ;
        $(attributes).set projects-to-build : $(now) $(dir) ;
    }

    rule explicit ( target-names * )
    {
        import project ;
        # If 'explicit' is used in a helper rule defined in Jamroot and
        # inherited by children, then most of the time we want 'explicit' to
        # operate on the Jamfile where the helper rule is invoked.
        local t = [ project.current ] ;
        for local n in $(target-names)
        {
            $(t).mark-target-as-explicit $(n) ;
        }
    }

    rule glob ( wildcards + : excludes * )
    {
        import project ;
        return [ project.glob-internal [ project.current ] : $(wildcards) :
            $(excludes) : glob ] ;
    }

    rule glob-tree ( wildcards + : excludes * )
    {
        import project ;

        if $(wildcards:D) || $(excludes:D)
        {
            errors.user-error The patterns to 'glob-tree' may not include
                directory ;
        }
        return [ project.glob-internal [ project.current ] : $(wildcards) :
            $(excludes) : glob-tree ] ;
    }

    # Calculates conditional requirements for multiple requirements at once.
    # This is a shorthand to reduce duplication and to keep an inline
    # declarative syntax. For example:
    #
    #   lib x : x.cpp : [ conditional <toolset>gcc <variant>debug :
    #       <define>DEBUG_EXCEPTION <define>DEBUG_TRACE ] ;
    #
    rule conditional ( condition + : requirements * )
    {
        local condition = $(condition:J=,) ;
        if [ MATCH (:) : $(condition) ]
        {
            return $(condition)$(requirements) ;
        }
        else
        {
            return $(condition):$(requirements) ;
        }
    }
}