[PATCH v4 15/16] index-helper: optionally automatically run

[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>
---
 Documentation/config.txt |  4 ++++
 git.c                    | 35 ++++++++++++++++++++++++++++++++++-
 t/t7900-index-helper.sh  | 16 ++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 2cd6bdd..8ec8824 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1852,6 +1852,10 @@ index.version::
 	Specify the version with which new index files should be
 	initialized.  This does not affect existing repositories.
 
+indexhelper.autorun::
+	Automatically run git index-helper when any builtin git
+	command is run inside a repository.
+
 init.templateDir::
 	Specify the directory from which templates will be copied.
 	(See the "TEMPLATE DIRECTORY" section of linkgit:git-init[1].)
diff --git a/git.c b/git.c
index 6cc0c07..7d27782 100644
--- a/git.c
+++ b/git.c
@@ -521,6 +521,37 @@ 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", "--autorun", NULL};
+
+	if (!(cmd->option & NEED_WORK_TREE))
+		return;
+
+	if (want_auto_index_helper() <= 0)
+		return;
+
+	trace_argv_printf(argv, "trace: auto index-helper:");
+
+	if (run_command_v_opt(argv,
+			      RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT))
+		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 +567,10 @@ 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/t/t7900-index-helper.sh b/t/t7900-index-helper.sh
index eeca483..8b969d3 100755
--- a/t/t7900-index-helper.sh
+++ b/t/t7900-index-helper.sh
@@ -49,4 +49,20 @@ test_expect_success 'index-helper is quiet with --autorun' '
 	git index-helper --autorun
 '
 
+test_expect_success 'index-helper autorun works' '
+	rm -f .git/index-helper.path &&
+	git status &&
+	test_path_is_missing .git/index-helper.path &&
+	test_config indexhelper.autorun true &&
+	git status &&
+	test -L .git/index-helper.path &&
+	git status 2>err &&
+	test -L .git/index-helper.path &&
+	! grep -q . err &&
+	git index-helper --kill &&
+	test_config indexhelper.autorun false &&
+	git status &&
+	test_path_is_missing .git/index-helper.path
+'
+
 test_done
-- 
2.4.2.767.g62658d5-twtrsrc