[PATCH 18/19] index-helper: autorun

[David Turner <dturner@twopensource.com>]

Introduce a new config option, indexhelper.autorun, to automatically
run git index-helper before starting up a builtin git command.  This
enables users to keep index-helper running without manual
intervention.

Signed-off-by: David Turner <dturner@twopensource.com>
---
 git.c                   | 38 +++++++++++++++++++++++++++++++++++++-
 index-helper.c          | 11 ++++++++++-
 t/t7900-index-helper.sh | 10 ++++++++++
 3 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/git.c b/git.c
index a4f6f71..ccf04ab 100644
--- a/git.c
+++ b/git.c
@@ -521,6 +521,40 @@ static void strip_extension(const char **argv)
 #define strip_extension(cmd)
 #endif
 
+static int want_auto_index_helper(void)
+{
+	int want = -1;
+	const char *value = NULL;
+	const char *key = "indexhelper.autorun";
+
+	if (git_config_key_is_valid(key) &&
+	    !git_config_get_value(key, &value)) {
+		int b = git_config_maybe_bool(key, value);
+		want = b >= 0 ? b : 0;
+	}
+	return want;
+}
+
+static void maybe_run_index_helper(struct cmd_struct *cmd)
+{
+	const char *argv[] = {"git-index-helper", "--detach", "--auto", NULL};
+	int status;
+
+	if (!(cmd->option & NEED_WORK_TREE))
+		return;
+
+	if (want_auto_index_helper() <= 0)
+		return;
+
+	trace_argv_printf(argv, "trace: auto index-helper:");
+
+	status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
+
+	if (status) {
+		warning("You specified indexhelper.autorun, but running git-index-helper failed");
+	}
+}
+
 static void handle_builtin(int argc, const char **argv)
 {
 	const char *cmd;
@@ -536,8 +570,10 @@ static void handle_builtin(int argc, const char **argv)
 	}
 
 	builtin = get_builtin(cmd);
-	if (builtin)
+	if (builtin) {
+		maybe_run_index_helper(builtin);
 		exit(run_builtin(builtin, argc, argv));
+	}
 }
 
 static void execv_dashed_external(const char **argv)
diff --git a/index-helper.c b/index-helper.c
index a75da60..bc5c328 100644
--- a/index-helper.c
+++ b/index-helper.c
@@ -379,6 +379,7 @@ int main(int argc, char **argv)
 	int idle_in_minutes = 10, detach = 0;
 	int ignore_existing = 0;
 	int kill_existing = 0;
+	int nongit = 0, autorun = 0;
 	const char *pid_file;
 	struct option options[] = {
 		OPT_INTEGER(0, "exit-after", &idle_in_minutes,
@@ -388,6 +389,7 @@ int main(int argc, char **argv)
 		OPT_BOOL(0, "detach", &detach, "detach the process"),
 		OPT_BOOL(0, "ignore-existing", &ignore_existing, "run even if another index-helper seems to be running for this repo"),
 		OPT_BOOL(0, "kill", &kill_existing, "kill any running index-helper for this repo"),
+		OPT_BOOL(0, "auto", &autorun, "this is an automatic run of git index-helper, so certain errors can be solved by silently exiting"),
 		OPT_END()
 	};
 
@@ -397,11 +399,18 @@ int main(int argc, char **argv)
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(usage_text, options);
 
-	prefix = setup_git_directory();
+	prefix = setup_git_directory_gently(&nongit);
 	if (parse_options(argc, (const char **)argv, prefix,
 			  options, usage_text, 0))
 		die(_("too many arguments"));
 
+	if (nongit) {
+		if (autorun)
+			exit(0);
+		else
+			die("Not a git repository");
+	}
+
 	if (ignore_existing && kill_existing)
 		die(_("--ignore-existing and --kill don't make sense together"));
 
diff --git a/t/t7900-index-helper.sh b/t/t7900-index-helper.sh
index 6708180..e4f9564 100755
--- a/t/t7900-index-helper.sh
+++ b/t/t7900-index-helper.sh
@@ -20,4 +20,14 @@ test_expect_success 'index-helper creates usable pid file and can be killed' '
 	! kill -0 $pid
 '
 
+test_expect_success 'index-helper autorun works' '
+	rm -f .git/index-helper.pid &&
+	git status &&
+	test_path_is_missing .git/index-helper.pid &&
+	test_config indexhelper.autorun true &&
+	git status &&
+	test_path_is_file .git/index-helper.pid &&
+	git index-helper --kill
+'
+
 test_done
-- 
2.4.2.767.g62658d5-twtrsrc