[06/11] maintenance: add --task option

Commit Message

Derrick Stolee via GitGitGadget Aug. 6, 2020, 3:48 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 |  8 +++-
 builtin/gc.c                      | 61 +++++++++++++++++++++++++++++--
 t/t7900-maintenance.sh            | 27 ++++++++++++++
 3 files changed, 92 insertions(+), 4 deletions(-)

Patch

diff --git a/Documentation/git-maintenance.txt b/Documentation/git-maintenance.txt
index 35b0be7d40..5911213c9c 100644
--- a/Documentation/git-maintenance.txt
+++ b/Documentation/git-maintenance.txt
@@ -30,7 +30,9 @@  SUBCOMMANDS
 -----------
 
 run::
-	Run one or more maintenance tasks.
+	Run one or more maintenance tasks. If one or more `--task=<task>`
+	options are specified, then those tasks are run in the provided
+	order. Otherwise, only the `gc` task is run.
 
 TASKS
 -----
@@ -73,6 +75,10 @@  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 3b7b914d60..3d50ab7ac9 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -791,7 +791,9 @@  typedef int maintenance_task_fn(struct maintenance_opts *opts);
 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 {
@@ -814,13 +816,32 @@  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(struct maintenance_opts *opts)
 {
-	int i;
+	int i, found_selected = 0;
 	int result = 0;
 
+	for (i = 0; !found_selected && i < TASK__COUNT; i++)
+		found_selected = tasks[i].selected;
+
+	if (found_selected)
+		QSORT(tasks, TASK__COUNT, compare_tasks_by_selection);
+
 	for (i = 0; i < TASK__COUNT; i++) {
-		if (!tasks[i].enabled)
+		if (found_selected && !tasks[i].selected)
+			continue;
+
+		if (!found_selected && !tasks[i].enabled)
 			continue;
 
 		if (tasks[i].fn(opts)) {
@@ -832,6 +853,37 @@  static int maintenance_run(struct maintenance_opts *opts)
 	return result;
 }
 
+static int task_option_parse(const struct option *opt,
+			     const char *arg, int unset)
+{
+	int i, num_selected = 0;
+	struct maintenance_task *task = NULL;
+
+	BUG_ON_OPT_NEG(unset);
+
+	for (i = 0; i < TASK__COUNT; i++) {
+		num_selected += tasks[i].selected;
+		if (!strcasecmp(tasks[i].name, arg)) {
+			task = &tasks[i];
+		}
+	}
+
+	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 = num_selected + 1;
+
+	return 0;
+}
+
 int cmd_maintenance(int argc, const char **argv, const char *prefix)
 {
 	static struct maintenance_opts opts;
@@ -840,6 +892,9 @@  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 384294d111..bcc7131818 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -23,4 +23,31 @@  test_expect_success 'run [--auto|--quiet]' '
 	test_subcommand git gc --no-quiet <run-no-quiet.txt
 '
 
+test_expect_success 'run --task=<task>' '
+	GIT_TRACE2_EVENT="$(pwd)/run-commit-graph.txt" \
+		git maintenance run --task=commit-graph 2>/dev/null &&
+	GIT_TRACE2_EVENT="$(pwd)/run-gc.txt" \
+		git maintenance run --task=gc 2>/dev/null &&
+	GIT_TRACE2_EVENT="$(pwd)/run-commit-graph.txt" \
+		git maintenance run --task=commit-graph 2>/dev/null &&
+	GIT_TRACE2_EVENT="$(pwd)/run-both.txt" \
+		git maintenance run --task=commit-graph --task=gc 2>/dev/null &&
+	test_subcommand ! git gc --quiet <run-commit-graph.txt &&
+	test_subcommand git gc --quiet <run-gc.txt &&
+	test_subcommand git gc --quiet <run-both.txt &&
+	test_subcommand git commit-graph write --split --reachable --no-progress <run-commit-graph.txt &&
+	test_subcommand ! git commit-graph write --split --reachable --no-progress <run-gc.txt &&
+	test_subcommand git commit-graph write --split --reachable --no-progress <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