From cf5fd926c0fbe03d7991a0342c6a99605c60692e Mon Sep 17 00:00:00 2001
From: Matt McCutchen <hashproduct@gmail.com>
Date: Fri, 8 Jun 2007 15:05:21 -0400
Subject: [PATCH] - Revise and comment target metadata variables. - Add the
 beginning of mg-define-rule-dlc .

---
 src/mage.mk | 70 +++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 60 insertions(+), 10 deletions(-)

diff --git a/src/mage.mk b/src/mage.mk
index b86983a..3a5181a 100644
--- a/src/mage.mk
+++ b/src/mage.mk
@@ -65,14 +65,25 @@ $(opfx)%: $$($$(oid)@opr)
 
 # MAIN BUILD LOGIC
 
-# bar.g file format:
-#     bar@cmd:=cat foo >bar.tmp
-#     bar@warnings:=$(empty)yikes!
-# And if dependency-logging:
-# List of filename@revision, revision is x for exists and empty for doesn't
-# exist.  Later perhaps x will be the mtime.
-#     bar@deps:=included@x oops@
-# If bar is overridden, we clear all three variables.
+# Target metadata variables for bar: (*: stored in bar.g)
+#
+# bar@cmd:=cat foo >bar.tmp
+#     Generation command as given to the shell.*
+# bar@warnings:=$(empty)yikes!
+#     Stuff the command printed to stdout or stderr.*
+# bar@deps:=included@x oops@
+#     If dependency-logging, list of filename@revision used.  Revision is x for
+#     exists and empty for doesn't exist.  Later perhaps x will be the mtime.*
+# bar@gloaded:=1
+#     Set if Mage has loaded bar.g and hasn't changed it since then.
+# bar@uptodate:=1
+#     Set when Mage makes a file or depends on it being made.  Used to determine
+#     the next prerequisite to check for a dependency-logging command.
+# bar@generated:=1
+#     Set when Mage generates a file; suppresses warning replay.
+#
+# If the rule for bar is overridden, we clear the information from bar.g so that
+# it is as if bar.g didn't exist.
 
 # $(call gload,foo.o)
 # Make sure foo.o's genfile, if any, has been loaded.
@@ -138,7 +149,8 @@ define mg-file-from-genfile
 # HMMM Maybe errors should go to stderr???
 $1: MG-FORCE | $1.g
 	$$(call gload,$$@)
-	$$(if $$($$@@warnings),$$(if $$($$@@built),,$$(info $$($$@@cmd) # warning replay)$$(info $$($$@@warnings))),)
+	$$(eval $$@@uptodate:=1)
+	$$(if $$($$@@warnings),$$(if $$($$@@changed),,$$(info $$($$@@cmd) # warning replay)$$(info $$($$@@warnings))),)
 endef
 
 # If the target is unmanaged, we must run the rule; we'll see that the
@@ -151,6 +163,7 @@ mg-check-cmd=$(if $(call streq,$(cmd),$($(target)@cmd)),,x)
 # Just add additional prerequisites.
 # I don't think this can add patterns to implicit rules, but it should be able
 # to add specific prerequisites to uses of implicit rules.
+# TODO Make this work for dependency-logging commands if desired.
 define mg-define-prereq
 $(eval 
 $1.g: $2
@@ -184,7 +197,7 @@ define mg-generate
 		$(eval $(target)@cmd:=)$(eval $(target)@warnings:=)$(eval $(target)@deps:=)\
 	,\
 	$(if $?$(if $(wildcard $(target)),,x)$(mg-check-cmd),\
-	$(eval $(target)@gloaded:=)$(eval $(target)@built:=1)$(info $(cmd))\
+	$(eval $(target)@gloaded:=)$(eval $(target)@changed:=1)$(info $(cmd))\
 	@trap 'rm -f $(target).tmp $@.tmp' EXIT &&\
 	exec 3>$@.tmp && $(mg-assign-cmd) >&3 &&\
 	set -o pipefail && { $(mg-run-cmd) | tee /dev/fd/4 | $(mg-wrap-warnings) >&3; } 4>&1 &&\
@@ -198,6 +211,43 @@ mg-run-cmd={ ($(cmd)) 2>&1 && { [ -r $(target).tmp ] || { echo 'mage: error: Com
 mg-wrap-warnings=sed -re '1s/^/$(target)@warnings:=$$(empty)/; 1!s/^/$(target)@warnings+=$$(nl)/'
 mg-maybe-move-target={ cmp -s $(target) $(target).tmp || echo >$@ && mv -f $(target).tmp $(target); }
 
+# $(call mg-rule,target,static prerequisites,cmd,[dep converter])
+# Defines a rule with a dependency-logging command.
+# I haven't decided on the format for the dep converter yet.
+dlc-static-run-oid:=$(newoid)
+define mg-define-rule-dlc
+$(eval 
+
+# Copied stuff from mg-define-rule to modify as necessary
+
+## Define some target-specific variables.
+## It might look like we could use $*, but $1 most likely isn't %.
+#$1.g: target = $$(@:.g=)
+#$1.g: cmd = $(call mg-translate-cmd,$3)
+#$1.g: mg@ = $$(target).tmp
+#$1.g: mg^ = $$(filter-out MG-% /./%,$$^)
+#$1.g: mg+ = $$(filter-out MG-% /./%,$$+)
+#$1.g: mg< = $$(firstword $$(mg^))
+
+# 
+$1.g: MG-FORCE | $$$$(dlc-first-run-oid)$$$$(aname)$1.g $$$$(call dlc-setup-tgt,$(newoid))
+
+## Rule for the genfile.  Evidently all the prerequisites we want second-expanded
+## have to go on the same rule.
+#$1.g: $2 $$$$(mg-scout-target) MG-FORCE
+#	$$(mg-generate)
+
+
+$(mg-file-from-genfile)
+)
+endef
+
+define dlc-setup-tgt
+$(eval 
+
+)$1
+endef
+
 # END
 
 # We don't want anything we defined to become the default goal.
-- 
2.34.1