Makefile: generate doc versions via GIT-VERSION-GEN

The documentation we generate embeds information for the exact Git
version used as well as the date of the commit. This information is
injected by injecting attributes into the build process via command line
argument.

Refactor the logic so that we write the information into "asciidoc.conf"
and "asciidoctor-extensions.rb" via `GIT-VERSION-GEN` for AsciiDoc and
AsciiDoctor, respectively.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

5 files changed, 25 insertions, 15 deletions

diff --git a/Documentation/.gitignore b/Documentation/.gitignore
index a48448de32..649df89474 100644
--- a/Documentation/.gitignore
+++ b/Documentation/.gitignore
@@ -15,3 +15,5 @@ tmp-doc-diff/
 GIT-ASCIIDOCFLAGS
 /.build/
 /GIT-EXCLUDED-PROGRAMS
+/asciidoc.conf
+/asciidoctor-extensions.rb
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 0f55baa252..9371f29425 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -1,6 +1,8 @@
 # Import tree-wide shared Makefile behavior and libraries
 include ../shared.mak
 
+.PHONY: FORCE
+
 # Guard against environment variables
 MAN1_TXT =
 MAN5_TXT =
@@ -148,16 +150,12 @@ man5dir = $(mandir)/man5
 man7dir = $(mandir)/man7
 # DESTDIR =
 
-GIT_DATE := $(shell git show --quiet --pretty='%as')
-
 ASCIIDOC = asciidoc
 ASCIIDOC_EXTRA =
 ASCIIDOC_HTML = xhtml11
 ASCIIDOC_DOCBOOK = docbook
 ASCIIDOC_CONF = -f asciidoc.conf
-ASCIIDOC_COMMON = $(ASCIIDOC) $(ASCIIDOC_EXTRA) $(ASCIIDOC_CONF) \
-		-amanmanual='Git Manual' -amansource='Git $(GIT_VERSION)' \
-		-arevdate='$(GIT_DATE)'
+ASCIIDOC_COMMON = $(ASCIIDOC) $(ASCIIDOC_EXTRA) $(ASCIIDOC_CONF)
 ASCIIDOC_DEPS = asciidoc.conf GIT-ASCIIDOCFLAGS
 TXT_TO_HTML = $(ASCIIDOC_COMMON) -b $(ASCIIDOC_HTML)
 TXT_TO_XML = $(ASCIIDOC_COMMON) -b $(ASCIIDOC_DOCBOOK)
@@ -210,6 +208,14 @@ ASCIIDOC_DEPS = asciidoctor-extensions.rb GIT-ASCIIDOCFLAGS
 DBLATEX_COMMON =
 XMLTO_EXTRA += --skip-validation
 XMLTO_EXTRA += -x manpage.xsl
+
+asciidoctor-extensions.rb: asciidoctor-extensions.rb.in FORCE
+	$(QUIET_GEN)GIT_USER_AGENT="$(GIT_USER_AGENT)" $(SHELL_PATH) ../GIT-VERSION-GEN "$(shell pwd)/.." $< $@+
+	@if cmp $@+ $@ >/dev/null 2>&1; then $(RM) $@+; else mv $@+ $@; fi
+else
+asciidoc.conf: asciidoc.conf.in FORCE
+	$(QUIET_GEN)GIT_USER_AGENT="$(GIT_USER_AGENT)" $(SHELL_PATH) ../GIT-VERSION-GEN "$(shell pwd)/.." $< $@+
+	@if cmp $@+ $@ >/dev/null 2>&1; then $(RM) $@+; else mv $@+ $@; fi
 endif
 
 ASCIIDOC_DEPS += docinfo.html
@@ -341,6 +347,7 @@ clean:
 	$(RM) SubmittingPatches.txt
 	$(RM) $(cmds_txt) $(mergetools_txt) *.made
 	$(RM) GIT-ASCIIDOCFLAGS
+	$(RM) asciidoc.conf asciidoctor-extensions.rb
 
 docinfo.html: docinfo-html.in
 	$(QUIET_GEN)$(RM) $@ && cat $< >$@
@@ -364,7 +371,7 @@ manpage-cmd = $(QUIET_XMLTO)$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
 %.xml : %.txt $(ASCIIDOC_DEPS)
 	$(QUIET_ASCIIDOC)$(TXT_TO_XML) -d manpage -o $@ $<
 
-user-manual.xml: user-manual.txt user-manual.conf asciidoctor-extensions.rb GIT-ASCIIDOCFLAGS
+user-manual.xml: user-manual.txt user-manual.conf $(ASCIIDOC_DEPS)
 	$(QUIET_ASCIIDOC)$(TXT_TO_XML) -d book -o $@ $<
 
 technical/api-index.txt: technical/api-index-skel.txt \
@@ -373,7 +380,7 @@ technical/api-index.txt: technical/api-index-skel.txt \
 
 technical/%.html: ASCIIDOC_EXTRA += -a git-relative-html-prefix=../
 $(patsubst %,%.html,$(API_DOCS) technical/api-index $(TECH_DOCS)): %.html : %.txt \
-	asciidoc.conf GIT-ASCIIDOCFLAGS
+	$(ASCIIDOC_DEPS)
 	$(QUIET_ASCIIDOC)$(TXT_TO_HTML) $*.txt
 
 SubmittingPatches.txt: SubmittingPatches
@@ -416,13 +423,13 @@ $(patsubst %.txt,%.texi,$(MAN_TXT)): %.texi : %.xml
 howto-index.txt: howto-index.sh $(HOWTO_TXT)
 	$(QUIET_GEN)'$(SHELL_PATH_SQ)' ./howto-index.sh $(sort $(HOWTO_TXT)) >$@
 
-$(patsubst %,%.html,$(ARTICLES)) : %.html : %.txt
+$(patsubst %,%.html,$(ARTICLES)) : %.html : %.txt $(ASCIIDOC_DEPS)
 	$(QUIET_ASCIIDOC)$(TXT_TO_HTML) $*.txt
 
 WEBDOC_DEST = /pub/software/scm/git/docs
 
 howto/%.html: ASCIIDOC_EXTRA += -a git-relative-html-prefix=../
-$(patsubst %.txt,%.html,$(HOWTO_TXT)): %.html : %.txt GIT-ASCIIDOCFLAGS
+$(patsubst %.txt,%.html,$(HOWTO_TXT)): %.html : %.txt $(ASCIIDOC_DEPS)
 	$(QUIET_ASCIIDOC) \
 	sed -e '1,/^$$/d' $< | \
 	$(TXT_TO_HTML) - >$@
diff --git a/Documentation/asciidoc.conf b/Documentation/asciidoc.conf.in
index f6da6d1fbd..dbe36a52ea 100644
--- a/Documentation/asciidoc.conf
+++ b/Documentation/asciidoc.conf.in
@@ -21,6 +21,9 @@ tilde=&#126;
 apostrophe=&#39;
 backtick=&#96;
 litdd=&#45;&#45;
+manmanual='Git Manual'
+mansource='Git @GIT_VERSION@'
+revdate='@GIT_DATE@'
 
 ifdef::backend-docbook[]
 [linkgit-inlinemacro]
diff --git a/Documentation/asciidoctor-extensions.rb b/Documentation/asciidoctor-extensions.rb.in
index cb24480b63..c4c200dace 100644
--- a/Documentation/asciidoctor-extensions.rb
+++ b/Documentation/asciidoctor-extensions.rb.in
@@ -29,13 +29,9 @@ module Git
     class DocumentPostProcessor < Asciidoctor::Extensions::Postprocessor
       def process document, output
         if document.basebackend? 'docbook'
-          mansource = document.attributes['mansource']
-          manversion = document.attributes['manversion']
-          manmanual = document.attributes['manmanual']
           new_tags = "" \
-            "<refmiscinfo class=\"source\">#{mansource}</refmiscinfo>\n" \
-            "<refmiscinfo class=\"version\">#{manversion}</refmiscinfo>\n" \
-            "<refmiscinfo class=\"manual\">#{manmanual}</refmiscinfo>\n"
+            "<refmiscinfo class=\"source\">@GIT_VERSION@</refmiscinfo>\n" \
+            "<refmiscinfo class=\"manual\">Git Manual</refmiscinfo>\n"
           output = output.sub(/<\/refmeta>/, new_tags + "</refmeta>")
         end
         output
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index a1c8146f05..b4687784c1 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -53,6 +53,7 @@ fi
 
 GIT_VERSION=$(expr "$VN" : v*'\(.*\)')
 GIT_BUILT_FROM_COMMIT=$(git -C "$SOURCE_DIR" rev-parse -q --verify HEAD 2>/dev/null)
+GIT_DATE=$(git -C "$SOURCE_DIR" show --quiet --format='%as' 2>/dev/null)
 if test -z "$GIT_USER_AGENT"
 then
 	GIT_USER_AGENT="git/$GIT_VERSION"
@@ -72,6 +73,7 @@ sed -e "s|@GIT_VERSION@|$GIT_VERSION|" \
 	-e "s|@GIT_PATCH_LEVEL@|$GIT_PATCH_LEVEL|" \
 	-e "s|@GIT_BUILT_FROM_COMMIT@|$GIT_BUILT_FROM_COMMIT|" \
 	-e "s|@GIT_USER_AGENT@|$GIT_USER_AGENT|" \
+	-e "s|@GIT_DATE@|$GIT_DATE|" \
 	"$INPUT" >"$OUTPUT"+
 
 if ! test -f "$OUTPUT" || ! cmp "$OUTPUT"+ "$OUTPUT" >/dev/null