[v3,06/20] maintenance: add --task option

Commit Message

Johannes Schindelin via GitGitGadget July 30, 2020, 10:24 p.m. UTC

From: Derrick Stolee <[e-mail]>

A user may want to only run certain maintenance tasks in a certain
order. Add the --task=<task> option, which allows a user to specify an
ordered list of tasks to run. These cannot be run multiple times,
however.

Here is where our array of maintenance_task pointers becomes critical.
We can sort the array of pointers based on the task order, but we do not
want to move the struct data itself in order to preserve the hashmap
references. We use the hashmap to match the --task=<task> arguments into
the task struct data.

Keep in mind that the 'enabled' member of the maintenance_task struct is
a placeholder for a future 'maintenance.<task>.enabled' config option.
Thus, we use the 'enabled' member to specify which tasks are run when
the user does not specify any --task=<task> arguments. The 'enabled'
member should be ignored if --task=<task> appears.

Signed-off-by: Derrick Stolee <[e-mail]>
---
 Documentation/git-maintenance.txt |  4 +++
 builtin/gc.c                      | 59 +++++++++++++++++++++++++++++--
 t/t7900-maintenance.sh            | 23 ++++++++++++
 3 files changed, 84 insertions(+), 2 deletions(-)

Patch

diff --git a/Documentation/git-maintenance.txt b/Documentation/git-maintenance.txt
index 35b0be7d40..9204762e21 100644
--- a/Documentation/git-maintenance.txt
+++ b/Documentation/git-maintenance.txt
@@ -73,6 +73,10 @@  OPTIONS
 --quiet::
 	Do not report progress or other information over `stderr`.
 
+--task=<task>::
+	If this option is specified one or more times, then only run the
+	specified tasks in the specified order.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/builtin/gc.c b/builtin/gc.c
index ec1bbc3f9e..b7f64891cd 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -708,6 +708,7 @@  static const char * const builtin_maintenance_usage[] = {
 static struct maintenance_opts {
 	int auto_flag;
 	int quiet;
+	int tasks_selected;
 } opts;
 
 static int run_write_commit_graph(void)
@@ -789,7 +790,9 @@  typedef int maintenance_task_fn(void);
 struct maintenance_task {
 	const char *name;
 	maintenance_task_fn *fn;
-	unsigned enabled:1;
+	unsigned enabled:1,
+		 selected:1;
+	int selected_order;
 };
 
 enum maintenance_task_label {
@@ -812,13 +815,29 @@  static struct maintenance_task tasks[] = {
 	},
 };
 
+static int compare_tasks_by_selection(const void *a_, const void *b_)
+{
+	const struct maintenance_task *a, *b;
+
+	a = (const struct maintenance_task *)&a_;
+	b = (const struct maintenance_task *)&b_;
+
+	return b->selected_order - a->selected_order;
+}
+
 static int maintenance_run(void)
 {
 	int i;
 	int result = 0;
 
+	if (opts.tasks_selected)
+		QSORT(tasks, TASK__COUNT, compare_tasks_by_selection);
+
 	for (i = 0; i < TASK__COUNT; i++) {
-		if (!tasks[i].enabled)
+		if (opts.tasks_selected && !tasks[i].selected)
+			continue;
+
+		if (!opts.tasks_selected && !tasks[i].enabled)
 			continue;
 
 		if (tasks[i].fn()) {
@@ -830,6 +849,39 @@  static int maintenance_run(void)
 	return result;
 }
 
+static int task_option_parse(const struct option *opt,
+			     const char *arg, int unset)
+{
+	int i;
+	struct maintenance_task *task = NULL;
+
+	BUG_ON_OPT_NEG(unset);
+
+	opts.tasks_selected++;
+
+	for (i = 0; i < TASK__COUNT; i++) {
+		if (!strcasecmp(tasks[i].name, arg)) {
+			task = &tasks[i];
+			break;
+		}
+	}
+
+	if (!task) {
+		error(_("'%s' is not a valid task"), arg);
+		return 1;
+	}
+
+	if (task->selected) {
+		error(_("task '%s' cannot be selected multiple times"), arg);
+		return 1;
+	}
+
+	task->selected = 1;
+	task->selected_order = opts.tasks_selected;
+
+	return 0;
+}
+
 int cmd_maintenance(int argc, const char **argv, const char *prefix)
 {
 	static struct option builtin_maintenance_options[] = {
@@ -837,6 +889,9 @@  int cmd_maintenance(int argc, const char **argv, const char *prefix)
 			 N_("run tasks based on the state of the repository")),
 		OPT_BOOL(0, "quiet", &opts.quiet,
 			 N_("do not report progress or other information over stderr")),
+		OPT_CALLBACK_F(0, "task", NULL, N_("task"),
+			N_("run a specific task"),
+			PARSE_OPT_NONEG, task_option_parse),
 		OPT_END()
 	};
 
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index ff646abf7c..3cdccb24df 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -20,4 +20,27 @@  test_expect_success 'run [--auto|--quiet]' '
 	grep ",\"gc\",\"--quiet\"" run-quiet.txt
 '
 
+test_expect_success 'run --task=<task>' '
+	GIT_TRACE2_EVENT="$(pwd)/run-commit-graph.txt" git maintenance run --task=commit-graph &&
+	GIT_TRACE2_EVENT="$(pwd)/run-gc.txt" git maintenance run --task=gc &&
+	GIT_TRACE2_EVENT="$(pwd)/run-commit-graph.txt" git maintenance run --task=commit-graph &&
+	GIT_TRACE2_EVENT="$(pwd)/run-both.txt" git maintenance run --task=commit-graph --task=gc &&
+	! grep ",\"gc\"" run-commit-graph.txt  &&
+	grep ",\"gc\"" run-gc.txt  &&
+	grep ",\"gc\"" run-both.txt  &&
+	grep ",\"commit-graph\",\"write\"" run-commit-graph.txt  &&
+	! grep ",\"commit-graph\",\"write\"" run-gc.txt  &&
+	grep ",\"commit-graph\",\"write\"" run-both.txt
+'
+
+test_expect_success 'run --task=bogus' '
+	test_must_fail git maintenance run --task=bogus 2>err &&
+	test_i18ngrep "is not a valid task" err
+'
+
+test_expect_success 'run --task duplicate' '
+	test_must_fail git maintenance run --task=gc --task=gc 2>err &&
+	test_i18ngrep "cannot be selected multiple times" err
+'
+
 test_done