| /* |
| * |
| * Copyright 2015 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. |
| * |
| */ |
| |
| #import "GRPCCompletionQueue.h" |
| |
| #import <grpc/grpc.h> |
| |
| const grpc_completion_queue_attributes kCompletionQueueAttr = { |
| GRPC_CQ_CURRENT_VERSION, GRPC_CQ_NEXT, GRPC_CQ_DEFAULT_POLLING, NULL}; |
| |
| @implementation GRPCCompletionQueue |
| |
| + (instancetype)completionQueue { |
| static GRPCCompletionQueue *singleton = nil; |
| static dispatch_once_t onceToken; |
| dispatch_once(&onceToken, ^{ |
| singleton = [[self alloc] init]; |
| }); |
| return singleton; |
| } |
| |
| - (instancetype)init { |
| if ((self = [super init])) { |
| _unmanagedQueue = grpc_completion_queue_create( |
| grpc_completion_queue_factory_lookup(&kCompletionQueueAttr), &kCompletionQueueAttr, NULL); |
| |
| // This is for the following block to capture the pointer by value (instead |
| // of retaining self and doing self->_unmanagedQueue). This is essential |
| // because the block doesn't end until after grpc_completion_queue_shutdown |
| // is called, and we only want that to happen after nobody's using the queue |
| // anymore (i.e. on self dealloc). So the block would never end if it |
| // retained self. |
| grpc_completion_queue *unmanagedQueue = _unmanagedQueue; |
| |
| // Start a loop on a concurrent queue to read events from the completion |
| // queue and dispatch each. |
| static dispatch_once_t initialization; |
| static dispatch_queue_t gDefaultConcurrentQueue; |
| dispatch_once(&initialization, ^{ |
| gDefaultConcurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); |
| }); |
| dispatch_async(gDefaultConcurrentQueue, ^{ |
| while (YES) { |
| // The following call blocks until an event is available. |
| grpc_event event = |
| grpc_completion_queue_next(unmanagedQueue, gpr_inf_future(GPR_CLOCK_REALTIME), NULL); |
| GRPCQueueCompletionHandler handler; |
| switch (event.type) { |
| case GRPC_OP_COMPLETE: |
| handler = (__bridge_transfer GRPCQueueCompletionHandler)event.tag; |
| handler(event.success); |
| break; |
| case GRPC_QUEUE_SHUTDOWN: |
| grpc_completion_queue_destroy(unmanagedQueue); |
| return; |
| default: |
| [NSException raise:@"Unrecognized completion type" format:@""]; |
| } |
| }; |
| }); |
| } |
| return self; |
| } |
| |
| - (void)dealloc { |
| // This makes the completion queue produce a GRPC_QUEUE_SHUTDOWN event *after* |
| // all other pending events are flushed. What this means is all the blocks |
| // passed to the gRPC C library as void* are eventually called, even if some |
| // are called after self is dealloc'd. |
| grpc_completion_queue_shutdown(_unmanagedQueue); |
| } |
| @end |