functions.mk

ifndef BS__FUNCTIONS_MK
BS__FUNCTIONS_MK=1

# dirname
#
# Arguments: a file name
#
# Returns the directory containing the given file name. Differs from
# $(dir $(FOO)) in that this won't have a trailing slash. Grr.
dirname=$(patsubst %/,%,$(dir $(1)))

# get-default
#
# Arguments: argument string, default string
#
# If the argument string is non-empty, return it. Else, return the default string
get-default = $(if $(1),$(1),$(2))

# get-unless-default
#
# Arguments: argument string, default string
#
# If the argument string isn't the same as the default string, return it
get-unless-default = $(if $(filter-out $(2),$(1)),$(1))

# add-dir
#
# Arguments: list of directories to add.
#
# Adds all the given directories to the list of those which will be
# automatically created.
#
# This is stupid: one version of this function works on make 3.81
# but not make 3.82, while the version that works on 3.82 spews
# screenfuls of warnings on 3.81. Ugly hack time.
ifeq ($(MAKE_VERSION),3.81)
_do_add_dir=$(if $(filter $(1),$(DIRS)),,$(eval DIRS += $(1)))
_add_one_dir=$(call _do_add_dir,$(patsubst %/,%,$(1)/))
else
_do_add_dir=$(if $(filter $(1),$(DIRS)),,$(eval DIRS += $(1) $(1)/))
_add_one_dir=$(call _do_add_dir,$(patsubst %/,%,$(1)))
endif
add-dir=$(foreach d,$(1),$(call _add_one_dir,$(patsubst %/,%,$(d))))

# save-vars
#
# Arguments: list of variable names to save, unique tag name under
#            which to save them.
#
# Saves the current values of all the given variables under the tag name given,
# to be later retrieved by load-vars.
#
save-vars=$(eval __saved_vars_$(2)_=$(1)) \
		$(foreach v,$(1), $(eval __saved_$(v)_$(2)_=$(value $(v))))

# load-vars
#
# Arguments: tag name
#
# Restores the variables saved under the given tag name to their saved values.
#
load-vars=$(foreach v,$(__saved_vars_$(1)_), $(eval $(v)=$(value __saved_$(v)_$(1)_)))

# expand-target-variable
#
# Arguments: target name, variable name
#
# Returns the concatenated value of the given variable to use when building the
# named target.
#
# This consists of:
#  - the global default value
#  - the value specified in the target's subdirectory (if the variable name is
#    in SUBDIR_VARIABLES)
#  - the target-specific value specified in the target's subdirectory (if the
#    variable name is in PER_TARGET_VARIABLES)
#

expand-target-variable=$($(2)) \
			$(if $(filter $(2),$(SUBDIR_VARIABLES)),$($(SUBDIR_$(1))_$(2)),) \
			$(if $(filter $(2),$(TARGET_VARIABLES)),$($(1)_$(2)),) \
			$(if $(filter $(2),$(TARGET_VARIABLES)),$(_BS_INTERNAL_$(1)_$(2)),)

# get-target-variable
#
# Arguments: target name, variable name
#
# Returns the most specific defined value of the given variable for the named
# target. Unlike expand-target-variable which concatenates all defined versions,
# this returns only the most specific version.

_do_bs_first_defined = $(if $(1),$(1),$(if $(2),$(2),$(3)))
_bs_first_defined = $(call _do_bs_first_defined,$(strip $1),$(strip $(2)),$(strip $(3)))
get-target-variable = $(call _bs_first_defined, \
			$(if $(filter $(2),$(TARGET_VARIABLES)),$($(1)_$(2)),), \
			$(if $(filter $(2),$(SUBDIR_VARIABLES)),$($(SUBDIR_$(1))_$(2)),), \
			$($(2)) \
		       )

# expand-subdir-variable, get-subdir-variable
#
# As above, but for subdirectory variables not target ones
expand-subdir-variable = $($(2)) $(if $(filter $(2),$(SUBDIR_VARIABLES)),$($(1)_$(2)))
get-subdir-variable = $(call _bs_first_defined,$(if $(filter $(2),$(SUBDIR_VARIABLES)),$($(1)_$(2))),$($(2)))

# recurse-dir
#
# Arguments: A directory name
#
# Returns a space-separated list of all files in the given directory and all subdirectories,
# excluding those that 'wildcard' doesn't match (i.e. dotfiles).
#
# This is quite simplistic, and not aware of symlinks. Be careful.

recurse-dir = $(foreach f, $(wildcard $(1)/*), \
    $(if $(wildcard $(f)/.), \
        $(call recurse-dir,$(f)), \
        $(f)))


endif