build: Generate per-cycle ChangeLog files

We should generate a ChangeLog for each minor version cycle, starting
from the Git import date (since before that we used ChangeLog-style
commit messages that don't really look good with the Git ones).

For this reason we can take Cairo's Makefile.am.changelog file and,
after tweaking it to fit our use case, let it generate the correct
ChangeLogs on dist.

ChangeLog

@@ -1,5 +0,0 @@
-2008-12-08  Emmanuele Bassi  <ebassi@linux.intel.com>
-
-	* *: Clutter moved from Subversion to Git. If you are reading
-	this then you should use `git log` to read the changes from
-	the commit messages.

Makefile.am

@@ -1,5 +1,4 @@
 include $(top_srcdir)/build/autotools/Makefile.am.silent
-include $(top_srcdir)/build/autotools/Makefile.am.changelog
 
 NULL =
 
@@ -61,3 +60,5 @@ MAINTAINERCLEANFILES = 	\
 	Makefile.in 	\
 	missing 	\
 	$(NULL)
+
+include $(top_srcdir)/build/autotools/Makefile.am.changelog

build/autotools/Makefile.am.changelog

@@ -1,19 +1,78 @@
-PREV_RELEASE=git-import
+# Taken from Cairo - build/Makefile.am.changelog
+# Modified to fit the Clutter build environment
 
-changelog:
+CURR_CHANGELOG_VERSION=$(CLUTTER_MAJOR_VERSION).$$(echo "($(CLUTTER_MINOR_VERSION)+1)/2*2" | bc)
-	@if test -d "$(srcdir)/.git"; \
+# examines $version
-	then \
+PREV_CHANGELOG_VERSION=$$(if test "x$$(echo "($$version-0.1)*2/2"|bc)" = "x$$(echo "$$version*2/2"|bc)"; \
-		to=""; \
+			  then echo "$$version-$$(echo "$$version" | sed 's/[0-9]/0/g;s/[0-9]$$/2/')"; \
-		from="$(PREV_RELEASE)"; \
+			  else echo "$$version-1.0"; \
-		echo Creating ChangeLog && \
+			  fi | bc | sed 's/[.]0*/./;s/^0[.]\?$$/git-import/;s/[.]$$/.0/')
-		( cd "$(top_srcdir)" && \
+
-		  echo '# Generated by configure.  Do no edit.'; echo; \
+CHANGELOGS = ChangeLog \
-		  $(top_srcdir)/missing --run perl $(top_srcdir)/build/gen-changelog.pl $$from..$$to ) > ChangeLog.tmp \
+	`version=$(CURR_CHANGELOG_VERSION); \
-		&& mv -f ChangeLog.tmp $(top_distdir)/ChangeLog \
+	version=$(PREV_CHANGELOG_VERSION); \
-		|| ( rm -f ChangeLog.tmp ; \
+	while test "x$$version" != xgit-import; do \
-		     echo Failed to generate ChangeLog >&2 ); \
+		echo ChangeLog.pre-$$version; \
+		version=$(PREV_CHANGELOG_VERSION); \
+	done`
+
+MAINTAINERCLEANFILES += $(srcdir)/ChangeLog $(srcdir)/ChangeLog.pre-*
+CLEANFILES += $(srcdir)/ChangeLog.cache-*
+
+changelogs:
+	@$(MAKE) $(AM_MAKEFLAGS) $(CHANGELOGS)
+
+dist-hook: changelogs
+	changelogs="$(CHANGELOGS)"; \
+	for changelog in $$changelogs; do \
+		cp $(srcdir)/$$changelog $(distdir)/ 2>/dev/null || \
+		cp $$changelog $(distdir)/; \
+	done
+
+$(srcdir)/ChangeLog:
+	@if test -d "$(srcdir)/.git"; then \
+		version=$(CURR_CHANGELOG_VERSION); \
+		prev=$(PREV_CHANGELOG_VERSION).0; \
+		nearest_tag=`git describe | sed 's/-.*//'`; \
+		before=$(srcdir)/ChangeLog.cache-$$prev..$$nearest_tag; \
+		after=$(srcdir)/ChangeLog.cache-$$nearest_tag..; \
+		$(MAKE) $(AM_MAKEFLAGS) $$before $$after && \
+		echo Creating $@ && \
+		{ echo '# Generated by configure.  Do not edit.'; echo; \
+		  cat $$after; echo; cat $$before; } > $@; \
 	else \
-		echo A git checkout is required to generate a ChangeLog >&2; \
+		test -f $@ || \
+		(echo A git checkout is required to generate $@ >&2 && \
+		 echo A git checkout is required to generate this file >> $@); \
 	fi
 
-dist-hook: changelog
+DISTCLEANFILES += ChangeLog.cache-*
+
+ChangeLog.cache-*..: .git
+
+ChangeLog%: $(srcdir)/ChangeLog%
+
+$(srcdir)/ChangeLog.cache-% $(srcdir)/ChangeLog.pre-%:
+	@echo Creating $@
+	@if test -d "$(srcdir)/.git"; then \
+	  (cd "$(srcdir)" && \
+	  version=$$(echo "$@" | sed 's/.*ChangeLog\([.].*-\)\?//'); \
+	  if echo "$@" | grep -q '^ChangeLog[.]cache'; then \
+		spec=$$version; \
+	  else \
+		to=$$version; \
+		test "x$$version" = x && version=$(CURR_CHANGELOG_VERSION); \
+		from=$(PREV_CHANGELOG_VERSION); \
+		test "x$$to" = x || to=$$to.0; \
+		test "x$$from" = xgit-import || from=$$from.0; \
+		spec=$$from..$$to; \
+	  fi; \
+	  $(top_srcdir)/build/missing --run git log --stat "$$spec") > $@.tmp \
+	  && mv -f $@.tmp $@ \
+	  || ($(RM) $@.tmp; \
+	      echo Failed to generate $@, your $@ may be outdated >&2); \
+	else \
+	  echo A git checkout is required to generate $@ >&2; \
+	fi
+
+.PHONY: changelogs ChangeLog $(srcdir)/ChangeLog

configure.ac

@@ -50,11 +50,13 @@ AC_PREREQ([2.59])
 AC_INIT([clutter],
         [clutter_version],
         [http://bugzilla.o-hand.com/enter_bug.cgi?product=Clutter])
-AC_CONFIG_MACRO_DIR([build/autotools])
-AC_CONFIG_SRCDIR([clutter/clutter.h])
-AM_CONFIG_HEADER([config.h])
 
-AM_INIT_AUTOMAKE([1.9])
+AC_CONFIG_SRCDIR([clutter/clutter.h])
+AC_CONFIG_HEADERS([config.h])
+AC_CONFIG_AUX_DIR([build])
+AC_CONFIG_MACRO_DIR([build/autotools])
+
+AM_INIT_AUTOMAKE([1.9.6 foreign])
 
 CLUTTER_MAJOR_VERSION=clutter_major_version
 CLUTTER_MINOR_VERSION=clutter_minor_version