Convert flashrom to git

- Drop support for Subversion in the getrevision script and Makefile.
 - Refinement of getrevision to have a single function determining the
   new flashrom version string (based on git describe).
 - Add .gitignore and .gitattributes file (the latter to limit exports).
 - Restore modification dates of the exported files from the VCS.
 - Stop exporting VCS log dumps to CHANGELOG. This makes no sense.
 - Export VCS metadata needed by the Makefile to versioninfo.inc
 - Do not export the pre-"compiled" manpage. It can be generated like
   anything else from the code dump with versioninfo.inc
 - Add some initial client-side git hooks that get installed automatically
   on make runs:
   * pre-commit:
     - test for whitespace errors via git diff-index --check
   * commit-msg:
     - Use the up to date hook from gerrit to add Change-Id tags.
       Unlike the upstream hook, add them to fixup/squash changes too
       to allow for our staging process.
     - Test for duplicate sign-offs/acks.
   * When pushing to one of the upstream repositories check mandatory rules:
      - existing signoffs and acks in all new commits
      - no deletions of branches
      - no new branches other than versioned branches (e.g., 0.0.x)
      - no history rewriting of branches
 - Various other small refinements, bikesheddings and cosmetic changes to
   slow down progress of flashrom and humanity as a whole.

Original-Change-Id: I64eef21982cac0a0a7419bcd2c8a936672ae9cb2
Original-Reviewed-on: https://review.coreboot.org/19206
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Original-Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Change-Id: I325edb7d9890c412a44ecacb5161268d3dbccc57
Signed-off-by: Stefan Tauner <stefan.tauner@gmx.at>
Signed-off-by: David Hendricks <dhendricks@fb.com>
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/21923
Acked-by: Stefan Tauner <stefan.tauner@gmx.at>

Makefile

@@ -526,23 +526,23 @@ LIB_OBJS = layout.o flashrom.o udelay.o programmer.o helpers.o
 
 CLI_OBJS = cli_classic.o cli_output.o cli_common.o print.o
 
-# Set the flashrom version string from the highest revision number of the checked out flashrom files.
-# Note to packagers: Any tree exported with "make export" or "make tarball"
-# will not require subversion. The downloadable snapshots are already exported.
-SVNVERSION := $(shell ./util/getrevision.sh -u 2>/dev/null )
+# versioninfo.inc stores metadata required to build a packaged flashrom. It is generated by the export rule and
+# imported below. If versioninfo.inc is not found and the variables are not defined by the user, the info will
+# be obtained using util/getrevision.sh, which is the common case during development.
+-include versioninfo.inc
+VERSION ?= $(shell ./util/getrevision.sh --revision)
+MAN_DATE ?= $(shell ./util/getrevision.sh --date $(PROGRAM).8.tmpl 2>/dev/null)
 
-RELEASE := 0.9.9
-VERSION := $(RELEASE)-$(SVNVERSION)
-RELEASENAME ?= $(VERSION)
+SCMDEF := -D'FLASHROM_VERSION="$(VERSION)"'
 
-SVNDEF := -D'FLASHROM_VERSION="$(VERSION)"'
+# No spaces in release names unless set explicitly
+RELEASENAME ?= $(shell echo "$(VERSION)" | sed -e 's/ /_/')
 
-# Inform user if there is no meaningful version string. If there is version information from a VCS print
-# something anyway because $(info...) will print a line break in any case which would look suspicious.
-# The && between the echos is a workaround for old versions of GNU make that issue the error "unterminated
-# variable reference" if a semicolon is used instead.
-$(info $(shell ./util/getrevision.sh -c 2>/dev/null || echo "Files don't seem to be under version control." && \
-	echo "Replacing all version templates with $(VERSION)." ))
+# Inform user of the version string
+$(info Replacing all version templates with $(VERSION).)
+
+# If a VCS is found then try to install hooks.
+$(shell ./util/getrevision.sh -c 2>/dev/null && ./util/git-hooks/install.sh)
 
 ###############################################################################
 # Default settings of CONFIG_* variables.
@@ -1024,7 +1024,7 @@ libflashrom.a: $(LIBFLASHROM_OBJS)
 TAROPTIONS = $(shell LC_ALL=C tar --version|grep -q GNU && echo "--owner=root --group=root")
 
 %.o: %.c .features
-	$(CC) -MMD $(CFLAGS) $(CPPFLAGS) $(FLASHROM_CFLAGS) $(FEATURE_CFLAGS) $(SVNDEF) -o $@ -c $<
+	$(CC) -MMD $(CFLAGS) $(CPPFLAGS) $(FLASHROM_CFLAGS) $(FEATURE_CFLAGS) $(SCMDEF) -o $@ -c $<
 
 # Make sure to add all names of generated binaries here.
 # This includes all frontends and libflashrom.
@@ -1349,7 +1349,7 @@ $(PROGRAM).8.html: $(PROGRAM).8
 
 $(PROGRAM).8: $(PROGRAM).8.tmpl
 	@# Add the man page change date and version to the man page
-	@sed -e 's#.TH FLASHROM 8 ".*".*#.TH FLASHROM 8 "$(shell ./util/getrevision.sh -d $(PROGRAM).8.tmpl 2>/dev/null)" "$(VERSION)"#' <$< >$@
+	@sed -e 's#.TH FLASHROM 8 ".*".*#.TH FLASHROM 8 "$(MAN_DATE)" "$(VERSION)"#' <$< >$@
 
 install: $(PROGRAM)$(EXEC_SUFFIX) $(PROGRAM).8
 	mkdir -p $(DESTDIR)$(PREFIX)/sbin
@@ -1357,25 +1357,42 @@ install: $(PROGRAM)$(EXEC_SUFFIX) $(PROGRAM).8
 	$(INSTALL) -m 0755 $(PROGRAM)$(EXEC_SUFFIX) $(DESTDIR)$(PREFIX)/sbin
 	$(INSTALL) -m 0644 $(PROGRAM).8 $(DESTDIR)$(MANDIR)/man8
 
-export: $(PROGRAM).8
-	@rm -rf $(EXPORTDIR)/flashrom-$(RELEASENAME)
-	@svn export -r BASE . $(EXPORTDIR)/flashrom-$(RELEASENAME)
-	@sed "s/^SVNVERSION.*/SVNVERSION := $(SVNVERSION)/" Makefile >$(EXPORTDIR)/flashrom-$(RELEASENAME)/Makefile
-	@cp $(PROGRAM).8 "$(EXPORTDIR)/flashrom-$(RELEASENAME)/$(PROGRAM).8"
-	@svn log >$(EXPORTDIR)/flashrom-$(RELEASENAME)/ChangeLog
-	@echo Exported $(EXPORTDIR)/flashrom-$(RELEASENAME)/
+_export: $(PROGRAM).8
+	@rm -rf "$(EXPORTDIR)/flashrom-$(RELEASENAME)"
+	@mkdir -p "$(EXPORTDIR)/flashrom-$(RELEASENAME)"
+	@git archive HEAD | tar -x -C "$(EXPORTDIR)/flashrom-$(RELEASENAME)"
+#	Generate versioninfo.inc containing metadata that would not be available in exported sources otherwise.
+	@echo "VERSION = $(VERSION)" > "$(EXPORTDIR)/flashrom-$(RELEASENAME)/versioninfo.inc"
+	@echo "MAN_DATE = $(MAN_DATE)" >> "$(EXPORTDIR)/flashrom-$(RELEASENAME)/versioninfo.inc"
+#	Restore modification date of all tracked files not marked 'export-ignore' in .gitattributes.
+#	sed is required to filter out file names having the attribute set.
+#	The sed program saves the file name in the hold buffer and then checks if the respective value is 'set'.
+#	If so it ignores the rest of the program, which otherwise restores the file name and prints it.
+	@git ls-tree -r -z -t --full-name --name-only HEAD | \
+		git check-attr -z --stdin export-ignore | \
+		sed -zne 'x;n;n;{/^set$$/b;};x;p;' | \
+		xargs -0 sh -c 'for f; do \
+			touch -d $$(git log --pretty=format:%cI -1 HEAD -- "$$f") \
+				"$(EXPORTDIR)/flashrom-$(RELEASENAME)/$$f"; \
+		done' dummy_arg0
 
-tarball: export
-	@tar cjf $(EXPORTDIR)/flashrom-$(RELEASENAME).tar.bz2 -C $(EXPORTDIR)/ $(TAROPTIONS) flashrom-$(RELEASENAME)/
-	@rm -rf $(EXPORTDIR)/flashrom-$(RELEASENAME)
-	@echo Created $(EXPORTDIR)/flashrom-$(RELEASENAME).tar.bz2
+export: _export
+	@echo "Exported $(EXPORTDIR)/flashrom-$(RELEASENAME)/"
+
+tarball: _export
+	@tar -cz --format=ustar -f "$(EXPORTDIR)/flashrom-$(RELEASENAME).tar.gz" -C $(EXPORTDIR)/ \
+		$(TAROPTIONS) "flashrom-$(RELEASENAME)/"
+#	Delete the exported directory again because it is most likely what's expected by the user.
+	@rm -rf "$(EXPORTDIR)/flashrom-$(RELEASENAME)"
+	@echo Created "$(EXPORTDIR)/flashrom-$(RELEASENAME).tar.gz"
 
 djgpp-dos: clean
 	make CC=i586-pc-msdosdjgpp-gcc STRIP=i586-pc-msdosdjgpp-strip
+
 libpayload: clean
 	make CC="CC=i386-elf-gcc lpgcc" AR=i386-elf-ar RANLIB=i386-elf-ranlib
 
-.PHONY: all install clean distclean compiler hwlibs features export tarball djgpp-dos featuresavailable libpayload
+.PHONY: all install clean distclean compiler hwlibs features _export export tarball featuresavailable libpayload
 
 # Disable implicit suffixes and built-in rules (for performance and profit)
 .SUFFIXES: