1 /* 2 * 3 * Copyright 2016 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 #ifndef GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H 20 #define GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H 21 22 #include <grpc/support/port_platform.h> 23 24 #include "src/core/lib/channel/channel_stack_builder.h" 25 #include "src/core/lib/surface/channel_stack_type.h" 26 #include "src/core/lib/transport/transport.h" 27 28 #define GRPC_CHANNEL_INIT_BUILTIN_PRIORITY 10000 29 30 /// This module provides a way for plugins (and the grpc core library itself) 31 /// to register mutators for channel stacks. 32 /// It also provides a universal entry path to run those mutators to build 33 /// a channel stack for various subsystems. 34 35 /// One stage of mutation: call functions against \a builder to influence the 36 /// finally constructed channel stack 37 typedef bool (*grpc_channel_init_stage)(grpc_channel_stack_builder* builder, 38 void* arg); 39 40 /// Global initialization of the system 41 void grpc_channel_init_init(void); 42 43 /// Register one stage of mutators. 44 /// Stages are run in priority order (lowest to highest), and then in 45 /// registration order (in the case of a tie). 46 /// Stages are registered against one of the pre-determined channel stack 47 /// types. 48 void grpc_channel_init_register_stage(grpc_channel_stack_type type, 49 int priority, 50 grpc_channel_init_stage stage_fn, 51 void* stage_arg); 52 53 /// Finalize registration. No more calls to grpc_channel_init_register_stage are 54 /// allowed. 55 void grpc_channel_init_finalize(void); 56 /// Shutdown the channel init system 57 void grpc_channel_init_shutdown(void); 58 59 /// Construct a channel stack of some sort: see channel_stack.h for details 60 /// \a type is the type of channel stack to create 61 /// \a prefix_bytes is the number of bytes before the channel stack to allocate 62 /// \a args are configuration arguments for the channel stack 63 /// \a initial_refs is the initial refcount to give the channel stack 64 /// \a destroy and \a destroy_arg specify how to destroy the channel stack 65 /// if destroy_arg is NULL, the returned value from this function will be 66 /// substituted 67 /// \a optional_transport is either NULL or a constructed transport object 68 /// Returns a pointer to the base of the memory allocated (the actual channel 69 /// stack object will be prefix_bytes past that pointer) 70 bool grpc_channel_init_create_stack(grpc_channel_stack_builder* builder, 71 grpc_channel_stack_type type); 72 73 #endif /* GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H */ 74