/*
 *
 * Copyright 2015-2016 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_H
#define GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_H

/* Internal API for completion queues */

#include <grpc/grpc.h>
#include "src/core/lib/debug/trace.h"
#include "src/core/lib/iomgr/pollset.h"

/* These trace flags default to 1. The corresponding lines are only traced
   if grpc_api_trace is also truthy */
extern grpc_tracer_flag grpc_cq_pluck_trace;
extern grpc_tracer_flag grpc_cq_event_timeout_trace;
extern grpc_tracer_flag grpc_trace_operation_failures;

#ifndef NDEBUG
extern grpc_tracer_flag grpc_trace_pending_tags;
extern grpc_tracer_flag grpc_trace_cq_refcount;
#endif

#ifdef __cplusplus
extern "C" {
#endif

typedef struct grpc_cq_completion {
  gpr_mpscq_node node;

  /** user supplied tag */
  void *tag;
  /** done callback - called when this queue element is no longer
      needed by the completion queue */
  void (*done)(grpc_exec_ctx *exec_ctx, void *done_arg,
               struct grpc_cq_completion *c);
  void *done_arg;
  /** next pointer; low bit is used to indicate success or not */
  uintptr_t next;
} grpc_cq_completion;

#ifndef NDEBUG
void grpc_cq_internal_ref(grpc_completion_queue *cc, const char *reason,
                          const char *file, int line);
void grpc_cq_internal_unref(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cc,
                            const char *reason, const char *file, int line);
#define GRPC_CQ_INTERNAL_REF(cc, reason) \
  grpc_cq_internal_ref(cc, reason, __FILE__, __LINE__)
#define GRPC_CQ_INTERNAL_UNREF(ec, cc, reason) \
  grpc_cq_internal_unref(ec, cc, reason, __FILE__, __LINE__)
#else
void grpc_cq_internal_ref(grpc_completion_queue *cc);
void grpc_cq_internal_unref(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cc);
#define GRPC_CQ_INTERNAL_REF(cc, reason) grpc_cq_internal_ref(cc)
#define GRPC_CQ_INTERNAL_UNREF(ec, cc, reason) grpc_cq_internal_unref(ec, cc)
#endif

/* Flag that an operation is beginning: the completion channel will not finish
   shutdown until a corrensponding grpc_cq_end_* call is made.
   \a tag is currently used only in debug builds. Return true on success, and
   false if completion_queue has been shutdown. */
bool grpc_cq_begin_op(grpc_completion_queue *cc, void *tag);

/* Queue a GRPC_OP_COMPLETED operation; tag must correspond to the tag passed to
   grpc_cq_begin_op */
void grpc_cq_end_op(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cc,
                    void *tag, grpc_error *error,
                    void (*done)(grpc_exec_ctx *exec_ctx, void *done_arg,
                                 grpc_cq_completion *storage),
                    void *done_arg, grpc_cq_completion *storage);

grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc);

bool grpc_cq_can_listen(grpc_completion_queue *cc);

grpc_cq_completion_type grpc_get_cq_completion_type(grpc_completion_queue *cc);

int grpc_get_cq_poll_num(grpc_completion_queue *cc);

grpc_completion_queue *grpc_completion_queue_create_internal(
    grpc_cq_completion_type completion_type, grpc_cq_polling_type polling_type);

#ifdef __cplusplus
}
#endif

#endif /* GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_H */