Completion queue creation API change (JUST API change. No functionality change)

include/grpc/grpc.h

@@ -93,9 +93,51 @@ GRPCAPI const char *grpc_version_string(void);
 /** Return a string specifying what the 'g' in gRPC stands for */
 GRPCAPI const char *grpc_g_stands_for(void);
 
-/** Create a completion queue */
+/** Specifies the type of APIs to use to pop events from the completion queue */
+typedef enum {
+  /** Events are popped out by calling grpc_completion_queue_next() API ONLY */
+  GRPC_CQ_NEXT = 1,
+  /** Events are popped out by calling grpc_completion_queue_pluck() API ONLY*/
+  GRPC_CQ_PLUCK
+} grpc_cq_completion_type;
+
+/** Completion queues internally MAY maintain a set of file descriptors in a
+    structure called 'pollset'. This enum specifies if a completion queue has an
+    associated pollset and any restrictions on the type of file descriptors that
+    can be present in the pollset.
+
+    I/O progress can only be made when grpc_completion_queue_next() or
+    grpc_completion_queue_pluck() are called on the completion queue (unless the
+    grpc_cq_polling_type is NON_POLLING) and hence it is very important to
+    actively call these APIs */
+typedef enum {
+  /** The completion queue will have an associated pollset and there is no
+      restriction on the type of file descriptors the pollset may contain */
+  DEFAULT_POLLING,
+
+  /** Similar to DEFAULT_POLLING except that the completion queues will not
+      contain any 'listening file descriptors' (i.e file descriptors used to
+      listen to incoming channels */
+  NON_LISTENING,
+
+  /** The completion queue will not have an associated pollset. Note that
+      grpc_completion_queue_next() or grpc_completion_queue_pluck() MUST still
+      be called to pop events from the completion queue; it is not required to
+      call them actively to make I/O progress */
+  NON_POLLING
+} grpc_cq_polling_type;
+
+/** Create a completion queue.
+
+    WARNING: This API is deprecated and will soon be deleted and replaced with
+    completion_queue_create_ex() */
 GRPCAPI grpc_completion_queue *grpc_completion_queue_create(void *reserved);
 
+/** Create a completion queue */
+GRPCAPI grpc_completion_queue *grpc_completion_queue_create_ex(
+    grpc_cq_completion_type completion_type, grpc_cq_polling_type polling_type,
+    void *reserved);
+
 /** Blocks until an event is available, the completion queue is being shut down,
     or deadline is reached.
 

src/core/lib/surface/completion_queue.c

@@ -64,6 +64,10 @@ typedef struct {
 struct grpc_completion_queue {
   /** owned by pollset */
   gpr_mu *mu;
+
+  grpc_cq_completion_type completion_type;
+  grpc_cq_polling_type polling_type;
+
   /** completed events */
   grpc_cq_completion completed_head;
   grpc_cq_completion *completed_tail;
@@ -79,6 +83,7 @@ struct grpc_completion_queue {
   int shutdown_called;
   int is_server_cq;
   /** Can the server cq accept incoming channels */
+  /* TODO: sreek - This will no longer be needed. Use polling_type set */
   int is_non_listening_server_cq;
   int num_pluckers;
   plucker pluckers[GRPC_MAX_COMPLETION_QUEUE_PLUCKERS];
@@ -110,7 +115,9 @@ int grpc_cq_event_timeout_trace;
 static void on_pollset_shutdown_done(grpc_exec_ctx *exec_ctx, void *cc,
                                      grpc_error *error);
 
-grpc_completion_queue *grpc_completion_queue_create(void *reserved) {
+grpc_completion_queue *grpc_completion_queue_create_ex(
+    grpc_cq_completion_type completion_type, grpc_cq_polling_type polling_type,
+    void *reserved) {
   grpc_completion_queue *cc;
   GPR_ASSERT(!reserved);
 
@@ -148,6 +155,10 @@ grpc_completion_queue *grpc_completion_queue_create(void *reserved) {
   return cc;
 }
 
+grpc_completion_queue *grpc_completion_queue_create(void *reserved) {
+  return grpc_completion_queue_create_ex(0, DEFAULT_POLLING, reserved);
+}
+
 #ifdef GRPC_CQ_REF_COUNT_DEBUG
 void grpc_cq_internal_ref(grpc_completion_queue *cc, const char *reason,
                           const char *file, int line) {
@@ -356,8 +367,9 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
       "deadline=gpr_timespec { tv_sec: %" PRId64
       ", tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
-      5, (cc, deadline.tv_sec, deadline.tv_nsec, (int)deadline.clock_type,
-          reserved));
+      5,
+      (cc, deadline.tv_sec, deadline.tv_nsec, (int)deadline.clock_type,
+       reserved));
   GPR_ASSERT(!reserved);
 
   dump_pending_tags(cc);
@@ -524,8 +536,9 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
         "deadline=gpr_timespec { tv_sec: %" PRId64
         ", tv_nsec: %d, clock_type: %d }, "
         "reserved=%p)",
-        6, (cc, tag, deadline.tv_sec, deadline.tv_nsec,
-            (int)deadline.clock_type, reserved));
+        6,
+        (cc, tag, deadline.tv_sec, deadline.tv_nsec, (int)deadline.clock_type,
+         reserved));
   }
   GPR_ASSERT(!reserved);
 
@@ -681,10 +694,14 @@ grpc_completion_queue *grpc_cq_from_pollset(grpc_pollset *ps) {
 }
 
 void grpc_cq_mark_non_listening_server_cq(grpc_completion_queue *cc) {
+  /* TODO: sreek - use cc->polling_type field here and add a validation check
+     (i.e grpc_cq_mark_non_listening_server_cq can only be called on a cc whose
+     polling_type is set to NON_LISTENING */
   cc->is_non_listening_server_cq = 1;
 }
 
 bool grpc_cq_is_non_listening_server_cq(grpc_completion_queue *cc) {
+  /* TODO (sreek) - return (cc->polling_type == NON_LISTENING) */
   return (cc->is_non_listening_server_cq == 1);
 }