kumquat-buildroot/package/pkg-virtual.mk

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################################################################################
# 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.
infra: consistently use double dollar signs inside inner-xxx-targets The inner-xxx-targets in the buildroot package infrastructures are evaluated using $(eval) which causes variable references to be a bit different than in regular make code. As we want most references to be expanded only at the time of the $(eval) we should not use standard references $(VAR) but rather use double dollar signs $$(VAR). This includes function references like $(call), $(subst), etc. The only exception is the reference to pkgdir/pkgname and numbered variables, which are parameters to the inner block: $(1), $(2), etc. This patch introduces consistent usage of double-dollar signs throughout the different inner-xxx-targets blocks. In some cases, this would potentially cause circular references, in particular when the value of HOST_FOO_VAR would be obtained from the corresponding FOO_VAR if HOST_FOO_VAR is not defined. In these cases, a test is added to check for a host package (the only case where such constructions are relevant; these are not circular). Benefits of these changes are: - behavior of variables is now again as expected. For example, setting $(2)_VERSION = virtual in pkg-virtual.mk will effectively work, while originally it would cause very odd results. - The output of 'make printvars' is now much more useful. This target shows the value of all variables, and the expression that led to that value. However, if the expression was coming from an inner-xxx-targets block, and was using single dollar signs, it would show in printvars as VAR = value (value) while if double dollar signs are used, it would effectively look like VAR = value (actual expression) as is intended. This improvement is for example effective for FOO_DL_VERSION, FOO_RAWNAME, FOO_SITE_METHOD and FOO_MAKE. The correctness of this patch has been verified using 'make printvars', 'make manual' and 'make legal-info' before and after applying this patch, and comparing the output. Insight-provided-by: Arnout Vandecappelle <arnout@mind.be> Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-11 21:12:24 +02:00
ifeq ($$(BR2_PACKAGE_HAS_$(2)),y)
ifeq ($$(call qstrip,$$(BR2_PACKAGE_PROVIDES_$(2))),)
$$(error No implementation selected for virtual package $(1). Configuration error)
endif
endif
$(2)_IS_VIRTUAL = YES
# A virtual package does not have any source associated
$(2)_SOURCE =
# Fake a version string, so it looks nicer in the build log
$(2)_VERSION = virtual
# This must be repeated from inner-generic-package, otherwise we get an empty
# _DEPENDENCIES
infra: consistently use double dollar signs inside inner-xxx-targets The inner-xxx-targets in the buildroot package infrastructures are evaluated using $(eval) which causes variable references to be a bit different than in regular make code. As we want most references to be expanded only at the time of the $(eval) we should not use standard references $(VAR) but rather use double dollar signs $$(VAR). This includes function references like $(call), $(subst), etc. The only exception is the reference to pkgdir/pkgname and numbered variables, which are parameters to the inner block: $(1), $(2), etc. This patch introduces consistent usage of double-dollar signs throughout the different inner-xxx-targets blocks. In some cases, this would potentially cause circular references, in particular when the value of HOST_FOO_VAR would be obtained from the corresponding FOO_VAR if HOST_FOO_VAR is not defined. In these cases, a test is added to check for a host package (the only case where such constructions are relevant; these are not circular). Benefits of these changes are: - behavior of variables is now again as expected. For example, setting $(2)_VERSION = virtual in pkg-virtual.mk will effectively work, while originally it would cause very odd results. - The output of 'make printvars' is now much more useful. This target shows the value of all variables, and the expression that led to that value. However, if the expression was coming from an inner-xxx-targets block, and was using single dollar signs, it would show in printvars as VAR = value (value) while if double dollar signs are used, it would effectively look like VAR = value (actual expression) as is intended. This improvement is for example effective for FOO_DL_VERSION, FOO_RAWNAME, FOO_SITE_METHOD and FOO_MAKE. The correctness of this patch has been verified using 'make printvars', 'make manual' and 'make legal-info' before and after applying this patch, and comparing the output. Insight-provided-by: Arnout Vandecappelle <arnout@mind.be> Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-11 21:12:24 +02:00
ifeq ($(4),host)
$(2)_DEPENDENCIES ?= $$(filter-out host-skeleton host-toolchain $(1),\
infra: consistently use double dollar signs inside inner-xxx-targets The inner-xxx-targets in the buildroot package infrastructures are evaluated using $(eval) which causes variable references to be a bit different than in regular make code. As we want most references to be expanded only at the time of the $(eval) we should not use standard references $(VAR) but rather use double dollar signs $$(VAR). This includes function references like $(call), $(subst), etc. The only exception is the reference to pkgdir/pkgname and numbered variables, which are parameters to the inner block: $(1), $(2), etc. This patch introduces consistent usage of double-dollar signs throughout the different inner-xxx-targets blocks. In some cases, this would potentially cause circular references, in particular when the value of HOST_FOO_VAR would be obtained from the corresponding FOO_VAR if HOST_FOO_VAR is not defined. In these cases, a test is added to check for a host package (the only case where such constructions are relevant; these are not circular). Benefits of these changes are: - behavior of variables is now again as expected. For example, setting $(2)_VERSION = virtual in pkg-virtual.mk will effectively work, while originally it would cause very odd results. - The output of 'make printvars' is now much more useful. This target shows the value of all variables, and the expression that led to that value. However, if the expression was coming from an inner-xxx-targets block, and was using single dollar signs, it would show in printvars as VAR = value (value) while if double dollar signs are used, it would effectively look like VAR = value (actual expression) as is intended. This improvement is for example effective for FOO_DL_VERSION, FOO_RAWNAME, FOO_SITE_METHOD and FOO_MAKE. The correctness of this patch has been verified using 'make printvars', 'make manual' and 'make legal-info' before and after applying this patch, and comparing the output. Insight-provided-by: Arnout Vandecappelle <arnout@mind.be> Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-11 21:12:24 +02:00
$$(patsubst host-host-%,host-%,$$(addprefix host-,$$($(3)_DEPENDENCIES))))
endif
# Add dependency against the provider
infra: consistently use double dollar signs inside inner-xxx-targets The inner-xxx-targets in the buildroot package infrastructures are evaluated using $(eval) which causes variable references to be a bit different than in regular make code. As we want most references to be expanded only at the time of the $(eval) we should not use standard references $(VAR) but rather use double dollar signs $$(VAR). This includes function references like $(call), $(subst), etc. The only exception is the reference to pkgdir/pkgname and numbered variables, which are parameters to the inner block: $(1), $(2), etc. This patch introduces consistent usage of double-dollar signs throughout the different inner-xxx-targets blocks. In some cases, this would potentially cause circular references, in particular when the value of HOST_FOO_VAR would be obtained from the corresponding FOO_VAR if HOST_FOO_VAR is not defined. In these cases, a test is added to check for a host package (the only case where such constructions are relevant; these are not circular). Benefits of these changes are: - behavior of variables is now again as expected. For example, setting $(2)_VERSION = virtual in pkg-virtual.mk will effectively work, while originally it would cause very odd results. - The output of 'make printvars' is now much more useful. This target shows the value of all variables, and the expression that led to that value. However, if the expression was coming from an inner-xxx-targets block, and was using single dollar signs, it would show in printvars as VAR = value (value) while if double dollar signs are used, it would effectively look like VAR = value (actual expression) as is intended. This improvement is for example effective for FOO_DL_VERSION, FOO_RAWNAME, FOO_SITE_METHOD and FOO_MAKE. The correctness of this patch has been verified using 'make printvars', 'make manual' and 'make legal-info' before and after applying this patch, and comparing the output. Insight-provided-by: Arnout Vandecappelle <arnout@mind.be> Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-06-11 21:12:24 +02:00
$(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)