package/pkg-virtual.mk

   1 ################################################################################
   2 # Virtual package infrastructure
   3 #
   4 # This file implements an infrastructure that eases development of
   5 # package .mk files for virtual packages. It should be used for all
   6 # virtual packages.
   7 #
   8 # See the Buildroot documentation for details on the usage of this
   9 # infrastructure
  10 #
  11 # In terms of implementation, this virtual infrastructure requires
  12 # the .mk file to only call the 'virtual-package' macro.
  13 #
  14 ################################################################################
  15
  16
  17 ################################################################################
  18 # inner-virtual-package -- defines the dependency rules of the virtual
  19 # package against its provider.
  20 #
  21 #  argument 1 is the lowercase package name
  22 #  argument 2 is the uppercase package name, including a HOST_ prefix
  23 #             for host packages
  24 #  argument 3 is the uppercase package name, without the HOST_ prefix
  25 #             for host packages
  26 #  argument 4 is the type (target or host)
  27 ################################################################################
  28
  29 # Note: putting this comment here rather than in the define block, otherwise
  30 # make would try to expand the $(error ...) in the comment, which is not
  31 # really what we want.
  32 # We need to use second-expansion for the $(error ...) call, below,
  33 # so it is not evaluated now, but as part of the generated make code.
  34
  35 define inner-virtual-package
  36
  37 # Ensure the virtual package has an implementation defined.
  38 ifeq ($$(BR2_PACKAGE_HAS_$(2)),y)
  39 ifeq ($$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2))),)
  40 $$(error No implementation selected for virtual package $(1). Configuration error)
  41 endif
  42 endif
  43
  44 $(2)_IS_VIRTUAL = YES
  45
  46 # Add dependency against the provider
  47 # For a host package, there is no corresponding BR2_PACKAGE_PROVIDES_HOST_FOO,
  48 # so we need to compute it from the target variant.
  49 ifeq ($(4),target)
  50 $(2)_DEPENDENCIES += $$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2)))
  51 else
  52 $(2)_DEPENDENCIES += host-$$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(3)))
  53 endif
  54
  55 # Call the generic package infrastructure to generate the necessary
  56 # make targets
  57 $(call inner-generic-package,$(1),$(2),$(3),$(4))
  58
  59 endef
  60
  61 ################################################################################
  62 # virtual-package -- the target generator macro for virtual packages
  63 ################################################################################
  64
  65 virtual-package = $(call inner-virtual-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)
  66 host-virtual-package = $(call inner-virtual-package,host-$(pkgname),$(call UPPERCASE,host-$(pkgname)),$(call UPPERCASE,$(pkgname)),host)