ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/include/depends.mk b/include/depends.mk
new file mode 100644
index 0000000..a858d4b
--- /dev/null
+++ b/include/depends.mk
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 2007-2020 OpenWrt.org
+
+# define a dependency on a subtree
+# parameters:
+# 1: directories/files
+# 2: directory dependency
+# 3: tempfile for file listings
+# 4: find options
+
+DEP_FINDPARAMS := -x "*/.svn*" -x ".*" -x "*:*" -x "*\!*" -x "* *" -x "*\\\#*" -x "*/.*_check" -x "*/.*.swp" -x "*/.pkgdir*"
+
+find_md5=find $(wildcard $(1)) -type f $(patsubst -x,-and -not -path,$(DEP_FINDPARAMS) $(2)) -printf "%p%T@\n" | sort | $(MKHASH) md5
+find_md5_reproducible=find $(wildcard $(1)) -type f $(patsubst -x,-and -not -path,$(DEP_FINDPARAMS) $(2)) -print0 | xargs -0 $(MKHASH) md5 | sort | $(MKHASH) md5
+
+define rdep
+ .PRECIOUS: $(2)
+ .SILENT: $(2)_check
+
+ $(2): $(2)_check
+ check-depends: $(2)_check
+
+ifneq ($(wildcard $(2)),)
+ $(2)_check::
+ $(if $(3), \
+ $(call find_md5,$(1),$(4)) > $(3).1; \
+ { [ \! -f "$(3)" ] || diff $(3) $(3).1 >/dev/null; } && \
+ ) \
+ { \
+ [ -f "$(2)_check.1" ] && mv "$(2)_check.1" "$(2)_check"; \
+ $(TOPDIR)/scripts/timestamp.pl $(DEP_FINDPARAMS) $(4) -n $(2) $(1) && { \
+ $(call debug_eval,$(SUBDIR),r,echo "No need to rebuild $(2)";) \
+ touch -r "$(2)" "$(2)_check"; \
+ } \
+ } || { \
+ $(call debug_eval,$(SUBDIR),r,echo "Need to rebuild $(2)";) \
+ touch "$(2)_check"; \
+ }
+ $(if $(3), mv $(3).1 $(3))
+else
+ $(2)_check::
+ $(if $(3), rm -f $(3) $(3).1)
+ $(call debug_eval,$(SUBDIR),r,echo "Target $(2) not built")
+endif
+
+endef
+
+ifeq ($(filter .%,$(MAKECMDGOALS)),$(if $(MAKECMDGOALS),$(MAKECMDGOALS),x))
+ define rdep
+ $(2): $(2)_check
+ endef
+endif