Commit 74398244 authored by Yann E. MORIN's avatar Yann E. MORIN Committed by Thomas Petazzoni
Browse files

packages: add infrastructure for virtual packages 



The virtual-package infrastructure allows to easily define a
virtual package in a single line:

    $ cat package/some-virtual-package/some-virtual-package.mk
    $(eval $(virtual-package))

And that's all. :-)

Thanks to Éric for his work on the manual, that prompted the
idea for this virtual-package infrastructure! ;-)

Signed-off-by: default avatar"Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Eric Le Bihan <eric.le.bihan.dev@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Cc: Mike Zick <minimod@morethan.org>
Reviewed-by: default avatarSamuel Martin <s.martin49@gmail.com>
Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
parent 7862abad

package/Makefile.in

+1 −0
Original line number Diff line number Diff line
@@ -371,4 +371,5 @@ include package/pkg-cmake.mk 
include package/pkg-luarocks.mk

include package/pkg-perl.mk

include package/pkg-python.mk

include package/pkg-virtual.mk

include package/pkg-generic.mk

package/pkg-virtual.mk

0 → 100644
+66 −0
Original line number Diff line number Diff line 
################################################################################

# 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 =



# This must be repeated from inner-generic-package, otherwise we get an empty

# _DEPENDENCIES

$(2)_DEPENDENCIES ?= $(filter-out host-toolchain $(1),\

	$(patsubst host-host-%,host-%,$(addprefix host-,$($(3)_DEPENDENCIES))))



# 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)