fsmonitor--daemon: implement 'stop' and 'status' commands

Implement `stop` and `status` client commands to control and query the
status of a `fsmonitor--daemon` server process (and implicitly start a
server process if necessary).

Later commits will implement the actual server and monitor the file
system.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c
index f04987933796bfc81fccb844d9307dadc0fb6702..5e3178b8bddbc6c421dfc9860521dc2f4aacfaf0 100644 (file)
--- a/builtin/fsmonitor--daemon.c
+++ b/builtin/fsmonitor--daemon.c
@@ -7,10 +7,55 @@
 #include "khash.h"
 
 static const char * const builtin_fsmonitor__daemon_usage[] = {
+       N_("git fsmonitor--daemon stop"),
+       N_("git fsmonitor--daemon status"),
        NULL
 };
 
 #ifdef HAVE_FSMONITOR_DAEMON_BACKEND
+/*
+ * Acting as a CLIENT.
+ *
+ * Send a "quit" command to the `git-fsmonitor--daemon` (if running)
+ * and wait for it to shutdown.
+ */
+static int do_as_client__send_stop(void)
+{
+       struct strbuf answer = STRBUF_INIT;
+       int ret;
+
+       ret = fsmonitor_ipc__send_command("quit", &answer);
+
+       /* The quit command does not return any response data. */
+       strbuf_release(&answer);
+
+       if (ret)
+               return ret;
+
+       trace2_region_enter("fsm_client", "polling-for-daemon-exit", NULL);
+       while (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING)
+               sleep_millisec(50);
+       trace2_region_leave("fsm_client", "polling-for-daemon-exit", NULL);
+
+       return 0;
+}
+
+static int do_as_client__status(void)
+{
+       enum ipc_active_state state = fsmonitor_ipc__get_state();
+
+       switch (state) {
+       case IPC_STATE__LISTENING:
+               printf(_("fsmonitor-daemon is watching '%s'\n"),
+                      the_repository->worktree);
+               return 0;
+
+       default:
+               printf(_("fsmonitor-daemon is not watching '%s'\n"),
+                      the_repository->worktree);
+               return 1;
+       }
+}
 
 int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix)
 {
@@ -28,6 +73,12 @@ int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix)
                usage_with_options(builtin_fsmonitor__daemon_usage, options);
        subcmd = argv[0];
 
+       if (!strcmp(subcmd, "stop"))
+               return !!do_as_client__send_stop();
+
+       if (!strcmp(subcmd, "status"))
+               return !!do_as_client__status();
+
        die(_("Unhandled subcommand '%s'"), subcmd);
 }