From ece94d69369cd19ed0c501defcec84c679194c93 Mon Sep 17 00:00:00 2001
From: Evan Hunt <each@isc.org>
Date: Wed, 30 Mar 2022 11:18:23 -0700
Subject: [PATCH] fixup! fixup! WIP: Add loopmgr that replaces isc_app, and
 parts of isc_nm related to the uv_loops

---
 lib/isc/include/isc/loop.h | 24 ++++++++++++++++++++----
 lib/isc/loop.c             | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/lib/isc/include/isc/loop.h b/lib/isc/include/isc/loop.h
index 852c43ff86..91e451c014 100644
--- a/lib/isc/include/isc/loop.h
+++ b/lib/isc/include/isc/loop.h
@@ -81,25 +81,41 @@ isc_loopmgr_run(isc_loopmgr_t *loopmgr);
  * Requires:
  *\li	'loopmgr' is a valid loop manager.
  */
+void
+isc_loop_runjob(isc_loop_t *loop, isc_job_cb cb, void *cbarg);
+/*%<
+ * Schedule a single job to run in 'loop' in the next iteration
+ * of uv_run(): 'cb' will be called with argument 'cbarg'.
+ *
+ * Requires:
+ *\li	'loop' is a valid loop.
+ *\li	'loop' is the currently running loop, or the loop manager
+ *	associated with 'loop' is paused or has not yet been started.
+ */
 
 void
 isc_loopmgr_pause(isc_loopmgr_t *loopmgr);
 /*%<
- * Send pause events to all running loops in 'loopmgr' (except the
- * current one if called from one of the loops). All paused loops will
- * wait utnil isc_loopmgr_resume() is called before continuing.
+ * Send pause events to all running loops in 'loopmgr' except the
+ * current one. This can only be called from a running loop.
+ * All the paused loops will wait until isc_loopmgr_resume() is
+ * run in the calling loop before continuing.
  *
  * Requires:
  *\li	'loopmgr' is a valid loop manager.
+ *\li	We are in a running loop.
  */
 
 void
 isc_loopmgr_resume(isc_loopmgr_t *loopmgr);
 /*%<
- * Send resume events to all paused loops in 'loopmgr'.
+ * Send resume events to all paused loops in 'loopmgr'. This can
+ * only be called by a running loop (which must therefore be the
+ * loop that called isc_loopmgr_pause()).
  *
  * Requires:
  *\li	'loopmgr' is a valid loop manager.
+ *\li	We are in a running loop.
  */
 
 void
diff --git a/lib/isc/loop.c b/lib/isc/loop.c
index ac10a913a7..c1310dbdc3 100644
--- a/lib/isc/loop.c
+++ b/lib/isc/loop.c
@@ -370,6 +370,36 @@ isc_loopmgr_teardown(isc_loopmgr_t *loopmgr, isc_job_cb cb, void *cbarg) {
 	isc__loopmgr_schedule(loopmgr, isc_loop_dtor, cb, cbarg);
 }
 
+void
+isc_loop_runjob(isc_loop_t *loop, isc_job_cb cb, void *cbarg) {
+	isc_loopmgr_t *loopmgr = NULL;
+	isc_job_t *job = NULL;
+	int r;
+
+	REQUIRE(VALID_LOOP(loop));
+
+	loopmgr = loop->loopmgr;
+
+	REQUIRE(loop->tid == isc__loopmgr_tid_v ||
+		!atomic_load(&loopmgr->running) ||
+		atomic_load(&loopmgr->paused));
+
+	job = isc_mem_get(loop->mctx, sizeof(*job));
+	*job = (isc_job_t){
+		.cb = cb,
+		.cbarg = cbarg,
+	};
+
+	isc_mem_attach(loop->mctx, &job->mctx);
+
+	r = uv_idle_init(&loop->loop, &job->idle);
+	UV_RUNTIME_CHECK(uv_idle_init, r);
+	uv_handle_set_data((uv_handle_t *)&job->idle, job);
+
+	r = uv_idle_start(&job->idle, isc__job_cb);
+	UV_RUNTIME_CHECK(uv_idle_start, r);
+}
+
 void
 isc_loopmgr_run(isc_loopmgr_t *loopmgr) {
 	REQUIRE(VALID_LOOPMGR(loopmgr));
@@ -396,6 +426,7 @@ isc_loopmgr_run(isc_loopmgr_t *loopmgr) {
 void
 isc_loopmgr_pause(isc_loopmgr_t *loopmgr) {
 	REQUIRE(VALID_LOOPMGR(loopmgr));
+	REQUIRE(isc__loopmgr_tid_v != ISC_LOOPMGR_TID_UNKNOWN);
 
 	for (size_t i = 0; i < loopmgr->nloops; i++) {
 		isc_loop_t *loop = &loopmgr->loops[i];
@@ -415,6 +446,7 @@ isc_loopmgr_pause(isc_loopmgr_t *loopmgr) {
 void
 isc_loopmgr_resume(isc_loopmgr_t *loopmgr) {
 	REQUIRE(VALID_LOOPMGR(loopmgr));
+	REQUIRE(isc__loopmgr_tid_v != ISC_LOOPMGR_TID_UNKNOWN);
 
 	RUNTIME_CHECK(atomic_compare_exchange_strong(&loopmgr->paused,
 						     &(bool){ true }, false));