generate-cmds.sh: export all commands to command-list.h

The current generate-cmds.sh generates just enough to print "git help"
output. That is, it only extracts help text for common commands.

The script is now updated to extract help text for all commands and
keep command classification a new file, command-list.h. This will be
useful later:

- "git help -a" could print a short summary of all commands instead of
  just the common ones.

- "git" could produce a list of commands of one or more category. One
  of its use is to reduce another command classification embedded in
  git-completion.bash.

The new file can be generated but is not used anywhere yet. The plan
is we migrate away from common-cmds.h. Then we can kill off
common-cmds.h build rules and generation code (and also delete
duplicate content in command-list.h which we keep for now to not mess
generate-cmds.sh up too much).

PS. The new fixed column requirement on command-list.txt is
technically not needed. But it helps simplify the code a bit at this
stage. We could lift this restriction later if we want to.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 75 insertions, 10 deletions

diff --git a/.gitignore b/.gitignore
index 833ef3b0b7..d4c3914167 100644
--- a/.gitignore
+++ b/.gitignore
@@ -180,6 +180,7 @@
 /gitweb/static/gitweb.js
 /gitweb/static/gitweb.min.*
 /common-cmds.h
+/command-list.h
 *.tar.gz
 *.dsc
 *.deb
diff --git a/Makefile b/Makefile
index f181687250..2a8913ea21 100644
--- a/Makefile
+++ b/Makefile
@@ -757,7 +757,7 @@ LIB_FILE = libgit.a
 XDIFF_LIB = xdiff/lib.a
 VCSSVN_LIB = vcs-svn/lib.a
 
-GENERATED_H += common-cmds.h
+GENERATED_H += common-cmds.h command-list.h
 
 LIB_H = $(shell $(FIND) . \
 	-name .git -prune -o \
@@ -1938,6 +1938,11 @@ $(BUILT_INS): git$X
 common-cmds.h: generate-cmdlist.sh command-list.txt
 
 common-cmds.h: $(wildcard Documentation/git-*.txt)
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh command-list.txt COMMON >$@+ && mv $@+ $@
+
+command-list.h: generate-cmdlist.sh command-list.txt
+
+command-list.h: $(wildcard Documentation/git-*.txt)
 	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh command-list.txt >$@+ && mv $@+ $@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
@@ -2148,7 +2153,7 @@ else
 # Dependencies on header files, for platforms that do not support
 # the gcc -MMD option.
 #
-# Dependencies on automatically generated headers such as common-cmds.h
+# Dependencies on automatically generated headers such as common-cmds.h or command-list.h
 # should _not_ be included here, since they are necessary even when
 # building an object for the first time.
 
@@ -2527,7 +2532,7 @@ sparse: $(SP_OBJ)
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: common-cmds.h
+check: common-cmds.h command-list.h
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \
@@ -2775,7 +2780,7 @@ clean: profile-clean coverage-clean
 	$(RM) $(TEST_PROGRAMS) $(NO_INSTALL)
 	$(RM) -r bin-wrappers $(dep_dirs)
 	$(RM) -r po/build/
-	$(RM) *.pyc *.pyo */*.pyc */*.pyo common-cmds.h $(ETAGS_TARGET) tags cscope*
+	$(RM) *.pyc *.pyo */*.pyc */*.pyo common-cmds.h command-list.h $(ETAGS_TARGET) tags cscope*
 	$(RM) -r $(GIT_TARNAME) .doc-tmp-dir
 	$(RM) $(GIT_TARNAME).tar.gz git-core_$(GIT_VERSION)-*.tar.gz
 	$(RM) $(htmldocs).tar.gz $(manpages).tar.gz
diff --git a/command-list.txt b/command-list.txt
index a1fad28fd8..786536aba0 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -8,8 +8,8 @@ info         examine the history and state (see also: git help revisions)
 history      grow, mark and tweak your common history
 remote       collaborate (see also: git help workflows)
 
-### command list (do not change this line)
-# command name                          category [deprecated] [common]
+### command list (do not change this line, also do not change alignment)
+# command name                          category [category] [category]
 git-add                                 mainporcelain           worktree
 git-am                                  mainporcelain
 git-annotate                            ancillaryinterrogators
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index 31b6d886cb..870d3b626a 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -1,5 +1,27 @@
 #!/bin/sh
 
+die () {
+	echo "$@" >&2
+	exit 1
+}
+
+command_list () {
+	sed '1,/^### command list/d;/^#/d' "$1"
+}
+
+get_categories () {
+	tr ' ' '\n'|
+	grep -v '^$' |
+	sort |
+	uniq
+}
+
+category_list () {
+	command_list "$1" |
+	cut -c 40- |
+	get_categories
+}
+
 get_synopsis () {
 	sed -n '
 		/^NAME/,/'"$1"'/H
@@ -10,14 +32,51 @@ get_synopsis () {
 		}' "Documentation/$1.txt"
 }
 
+define_categories () {
+	echo
+	echo "/* Command categories */"
+	bit=0
+	category_list "$1" |
+	while read cat
+	do
+		echo "#define CAT_$cat (1UL << $bit)"
+		bit=$(($bit+1))
+	done
+	test "$bit" -gt 32 && die "Urgh.. too many categories?"
+}
+
+print_command_list () {
+	echo "static struct cmdname_help command_list[] = {"
+
+	command_list "$1" |
+	while read cmd rest
+	do
+		printf "	{ \"$cmd\", $(get_synopsis $cmd), 0"
+		for cat in $(echo "$rest" | get_categories)
+		do
+			printf " | CAT_$cat"
+		done
+		echo " },"
+	done
+	echo "};"
+}
+
 echo "/* Automatically generated by generate-cmdlist.sh */
 struct cmdname_help {
-	char name[16];
-	char help[80];
-	unsigned char group;
+	const char *name;
+	const char *help;
+	uint32_t group;
 };
+"
+if test -z "$2"
+then
+	define_categories "$1"
+	echo
+	print_command_list "$1"
+	exit 0
+fi
 
-static const char *common_cmd_groups[] = {"
+echo "static const char *common_cmd_groups[] = {"
 
 grps=grps$$.tmp
 match=match$$.tmp