buildroot/package/pkg-virtual.mk
Thomas De Schampheleire f6fc9abd10 pkg-virtual: simplify definition of FOO_VERSION to 'virtual'
As mentioned in the e-mail accompanying the introduction of the pkg-virtual
infrastructure [1], the definition of FOO_VERSION is 'strange'.

After the cleanup of single/double dollar signs in inner-generic-package,
the special construction in pkg-virtual is no longer needed and can be
simplified.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

[1] http://lists.busybox.net/pipermail/buildroot/2014-April/093670.html
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-14 19:10:08 +02:00

72 lines
2.8 KiB
Makefile

################################################################################
# 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 an 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
# A virtual package does not have any source associated
$(2)_SOURCE =
# Fake a version string, so it looks nicer in the build log
$(2)_VERSION = virtual
# This must be repeated from inner-generic-package, otherwise we get an empty
# _DEPENDENCIES
ifeq ($(4),host)
$(2)_DEPENDENCIES ?= $$(filter-out host-toolchain $(1),\
$$(patsubst host-host-%,host-%,$$(addprefix host-,$$($(3)_DEPENDENCIES))))
endif
# Add dependency against the provider
$(2)_DEPENDENCIES += $$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2)))
# 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)