Added grpc_cq_alarm

3 files changed, 104 insertions, 0 deletions

diff --git a/src/core/surface/completion_queue.c b/src/core/surface/completion_queue.c
index 5dac8ebcf8..368838860f 100644
--- a/src/core/surface/completion_queue.c
+++ b/src/core/surface/completion_queue.c
@@ -44,6 +44,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/atm.h>
 #include <grpc/support/log.h>
+#include <grpc/support/time.h>
 
 typedef struct {
   grpc_pollset_worker *worker;
@@ -354,3 +355,37 @@ grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc) {
 void grpc_cq_mark_server_cq(grpc_completion_queue *cc) { cc->is_server_cq = 1; }
 
 int grpc_cq_is_server_cq(grpc_completion_queue *cc) { return cc->is_server_cq; }
+
+static void do_nothing_end_completion(grpc_exec_ctx *exec_ctx, void *arg,
+                                      grpc_cq_completion *c) {}
+
+static void cq_alarm_cb(grpc_exec_ctx *exec_ctx, void *arg, int success) {
+    grpc_cq_alarm *cq_alarm = arg;
+    grpc_cq_end_op(exec_ctx, cq_alarm->cq, cq_alarm->tag, success,
+            do_nothing_end_completion, NULL, &cq_alarm->completion);
+}
+
+grpc_cq_alarm *grpc_cq_alarm_create(grpc_exec_ctx *exec_ctx,
+                                    grpc_completion_queue *cq,
+                                    gpr_timespec deadline, void *tag) {
+    grpc_cq_alarm *cq_alarm = gpr_malloc(sizeof(grpc_cq_alarm));
+
+    GRPC_CQ_INTERNAL_REF(cq, "cq_alarm");
+    cq_alarm->cq = cq;
+    cq_alarm->tag = tag;
+
+    grpc_alarm_init(exec_ctx, &cq_alarm->alarm, deadline, cq_alarm_cb, cq_alarm,
+                    gpr_now(GPR_CLOCK_MONOTONIC));
+    grpc_cq_begin_op(cq);
+    return cq_alarm;
+}
+
+void grpc_cq_alarm_cancel(grpc_exec_ctx *exec_ctx, grpc_cq_alarm *cq_alarm) {
+    grpc_alarm_cancel(exec_ctx, &cq_alarm->alarm);
+}
+
+void grpc_cq_alarm_destroy(grpc_exec_ctx *exec_ctx, grpc_cq_alarm *cq_alarm) {
+    grpc_cq_alarm_cancel(exec_ctx, cq_alarm);
+    GRPC_CQ_INTERNAL_UNREF(cq_alarm->cq, "cq_alarm");
+    gpr_free(cq_alarm);
+}
diff --git a/src/core/surface/completion_queue.h b/src/core/surface/completion_queue.h
index 5f8282e542..ab5b87c5c8 100644
--- a/src/core/surface/completion_queue.h
+++ b/src/core/surface/completion_queue.h
@@ -36,6 +36,7 @@
 
 /* Internal API for completion queues */
 
+#include "src/core/iomgr/alarm.h"
 #include "src/core/iomgr/pollset.h"
 #include <grpc/grpc.h>
 
@@ -51,6 +52,16 @@ typedef struct grpc_cq_completion {
   gpr_uintptr next;
 } grpc_cq_completion;
 
+/** An alarm associated with a completion queue. */
+typedef struct grpc_cq_alarm {
+  grpc_alarm alarm;
+  grpc_cq_completion completion;
+  /** completion queue where events about this alarm will be posted */
+  grpc_completion_queue *cq;
+  /** user supplied tag */
+  void *tag;
+} grpc_cq_alarm;
+
 #ifdef GRPC_CQ_REF_COUNT_DEBUG
 void grpc_cq_internal_ref(grpc_completion_queue *cc, const char *reason,
                           const char *file, int line);
@@ -83,4 +94,20 @@ grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc);
 void grpc_cq_mark_server_cq(grpc_completion_queue *cc);
 int grpc_cq_is_server_cq(grpc_completion_queue *cc);
 
+/** Create a completion queue alarm instance associated to \a cq.
+ *
+ * Once the alarm expires (at \a deadline) or it's cancelled (see ...), an event
+ * with tag \a tag will be added to \a cq. If the alarm expired, the event's
+ * success bit will be true, false otherwise (ie, upon cancellation). */
+grpc_cq_alarm *grpc_cq_alarm_create(grpc_exec_ctx *exec_ctx,
+                                    grpc_completion_queue *cq,
+                                    gpr_timespec deadline, void *tag);
+
+/** Cancel a completion queue alarm. Calling this function ove an alarm that has
+ * already run has no effect. */
+void grpc_cq_alarm_cancel(grpc_exec_ctx *exec_ctx, grpc_cq_alarm *cq_alarm);
+
+/** Destroy the given completion queue alarm, cancelling it in the process. */
+void grpc_cq_alarm_destroy(grpc_exec_ctx *exec_ctx, grpc_cq_alarm *cq_alarm);
+
 #endif /* GRPC_INTERNAL_CORE_SURFACE_COMPLETION_QUEUE_H */
diff --git a/test/core/surface/completion_queue_test.c b/test/core/surface/completion_queue_test.c
index e3fc789788..785093c60f 100644
--- a/test/core/surface/completion_queue_test.c
+++ b/test/core/surface/completion_queue_test.c
@@ -102,6 +102,47 @@ static void test_cq_end_op(void) {
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
+static void test_cq_alarm(void) {
+  grpc_completion_queue *cc;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+
+  LOG_TEST("test_cq_alarm");
+  cc = grpc_completion_queue_create(NULL);
+  {
+      /* regular expiry */
+      grpc_event ev;
+      void *tag = create_test_tag();
+      grpc_cq_alarm *cq_alarm = grpc_cq_alarm_create(
+          &exec_ctx, cc, GRPC_TIMEOUT_SECONDS_TO_DEADLINE(1), tag);
+
+      ev = grpc_completion_queue_next(cc, GRPC_TIMEOUT_SECONDS_TO_DEADLINE(2),
+                                      NULL);
+      GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
+      GPR_ASSERT(ev.tag == tag);
+      GPR_ASSERT(ev.success);
+      grpc_cq_alarm_destroy(&exec_ctx, cq_alarm);
+  }
+  {
+      /* cancellation */
+      grpc_event ev;
+      void *tag = create_test_tag();
+      grpc_cq_alarm *cq_alarm = grpc_cq_alarm_create(
+          &exec_ctx, cc, GRPC_TIMEOUT_SECONDS_TO_DEADLINE(2), tag);
+
+      grpc_cq_alarm_cancel(&exec_ctx, cq_alarm);
+      GPR_ASSERT(grpc_exec_ctx_flush(&exec_ctx) == 1);
+      ev = grpc_completion_queue_next(cc, GRPC_TIMEOUT_SECONDS_TO_DEADLINE(1),
+                                      NULL);
+      GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
+      GPR_ASSERT(ev.tag == tag);
+      GPR_ASSERT(ev.success == 0);
+      grpc_cq_alarm_destroy(&exec_ctx, cq_alarm);
+  }
+
+  shutdown_and_destroy(cc);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
 static void test_shutdown_then_next_polling(void) {
   grpc_completion_queue *cc;
   grpc_event event;
@@ -343,6 +384,7 @@ int main(int argc, char **argv) {
   test_shutdown_then_next_with_timeout();
   test_cq_end_op();
   test_pluck();
+  test_cq_alarm();
   test_threading(1, 1);
   test_threading(1, 10);
   test_threading(10, 1);