################################################################################ # Virtual package infrastructure # # This file implements an infrastructure that eases development of # package .mk files for virtual packages. It should be used for all # virtual packages. # # See the Buildroot documentation for details on the usage of this # infrastructure # # In terms of implementation, this virtual infrastructure requires # the .mk file to only call the 'virtual-package' macro. # ################################################################################ ################################################################################ # inner-virtual-package -- defines the dependency rules of the virtual # package against its provider. # # argument 1 is the lowercase package name # argument 2 is the uppercase package name, including a HOST_ prefix # for host packages # argument 3 is the uppercase package name, without the HOST_ prefix # for host packages # argument 4 is the type (target or host) ################################################################################ # Note: putting this comment here rather than in the define block, otherwise # make would try to expand the $(error ...) in the comment, which is not # really what we want. # We need to use second-expansion for the $(error ...) call, below, # so it is not evaluated now, but as part of the generated make code. define inner-virtual-package # Ensure the virtual package has an implementation defined. ifeq ($$(BR2_PACKAGE_HAS_$(2)),y) ifeq ($$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2))),) $$(error No implementation selected for virtual package $(1). Configuration error) endif endif # explicitly set these so we do not get confused by environment # variables with the same names. $(2)_VERSION = $(2)_SOURCE = $(2)_IS_VIRTUAL = YES # Add dependency against the provider # For a host package, there is no corresponding BR2_PACKAGE_PROVIDES_HOST_FOO, # so we need to compute it from the target variant. ifeq ($(4),target) $(2)_DEPENDENCIES += $$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2))) else ifeq ($$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2))),) # Inherit from target package BR2_PACKAGE_PROVIDES_FOO $(2)_DEPENDENCIES += host-$$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(3))) else # BR2_PACKAGE_PROVIDES_HOST_<pkg> is explicitly defined $(2)_DEPENDENCIES += $$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2))) endif endif # Call the generic package infrastructure to generate the necessary # make targets $(call inner-generic-package,$(1),$(2),$(3),$(4)) endef ################################################################################ # virtual-package -- the target generator macro for virtual packages ################################################################################ virtual-package = $(call inner-virtual-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target) host-virtual-package = $(call inner-virtual-package,host-$(pkgname),$(call UPPERCASE,host-$(pkgname)),$(call UPPERCASE,$(pkgname)),host)