# Define a standard rule helper
# If passed a last parameter value of with_local_version, we also define an
# extra rule that can build source files within the $(BUILD_DIR). This is useful
# for rules that can be applied for intermediate objects (for example, when
# going .png -> .cpp -> .o).

define rule_label
@ echo "$(shell printf "%-8s" $(strip $(1)))$(@:$(BUILD_DIR)/%=%)"
endef

# rule_for can define both global and local rules
#  - use local if the source can be an intermediate file
#  - use global if the source can be in the main tree
define rule_for
ifneq ($(filter global,$(5)),)
$(addprefix $$(BUILD_DIR)/,$(strip $(2))): $(strip $(3)) | $$$$(@D)/.
	@ echo "$(shell printf "%-8s" $(strip $(1)))$$(@:$$(BUILD_DIR)/%=%)"
	$(Q) $(4)
endif
ifneq ($(filter local,$(5)),)
$(addprefix $$(BUILD_DIR)/,$(strip $(2))): $(addprefix $$(BUILD_DIR)/,$(strip $(3)))
	@ echo "$(shell printf "%-8s" $(strip $(1)))$$(@:$$(BUILD_DIR)/%=%)"
	$(Q) $(4)
endif
endef

# Helper functions to work with variants

define direct_object_for
$(addprefix $(BUILD_DIR)/,$(addsuffix .o,$(basename $(1))))
endef

# Objects for source files in $(1) matching flavor $(2). A flavor is a dot
# separated list of variants (e.g. large.speed).
define flavored_object_for
$(call direct_object_for,$(call filter_variants,$(1),$(sort $(subst ., ,$(2)))))
endef

define object_for
$(call direct_object_for,$(call any_variant,$(1)))
endef

# Multi-arch helpers
ifdef ARCHS
ifndef ARCH

# This rule allow us to build any executable (%) for a specified ARCH ($1)
# We depend on a phony target to make sure this rule is always executed
.PHONY: force_remake
define rule_for_arch_executable
.PRECIOUS: $$(BUILD_DIR)/$(1)/%.$$(EXE)
$$(BUILD_DIR)/$(1)/%.$$(EXE): force_remake
	$(Q) echo "MAKE    ARCH=$(1)"
	$(Q) $$(MAKE) ARCH=$(1)  $$*.$$(EXE)
endef

$(foreach ARCH,$(ARCHS),$(eval $(call rule_for_arch_executable,$(ARCH))))

endif
endif