| /* |
| * |
| * Copyright 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. |
| * |
| */ |
| |
| #include "src/core/lib/channel/channel_stack_builder.h" |
| |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/string_util.h> |
| |
| grpc_core::TraceFlag grpc_trace_channel_stack_builder(false, |
| "channel_stack_builder"); |
| |
| typedef struct filter_node { |
| struct filter_node* next; |
| struct filter_node* prev; |
| const grpc_channel_filter* filter; |
| grpc_post_filter_create_init_func init; |
| void* init_arg; |
| } filter_node; |
| |
| struct grpc_channel_stack_builder { |
| // sentinel nodes for filters that have been added |
| filter_node begin; |
| filter_node end; |
| // various set/get-able parameters |
| grpc_channel_args* args; |
| grpc_transport* transport; |
| char* target; |
| const char* name; |
| }; |
| |
| struct grpc_channel_stack_builder_iterator { |
| grpc_channel_stack_builder* builder; |
| filter_node* node; |
| }; |
| |
| grpc_channel_stack_builder* grpc_channel_stack_builder_create(void) { |
| grpc_channel_stack_builder* b = |
| (grpc_channel_stack_builder*)gpr_zalloc(sizeof(*b)); |
| |
| b->begin.filter = nullptr; |
| b->end.filter = nullptr; |
| b->begin.next = &b->end; |
| b->begin.prev = &b->end; |
| b->end.next = &b->begin; |
| b->end.prev = &b->begin; |
| |
| return b; |
| } |
| |
| void grpc_channel_stack_builder_set_target(grpc_channel_stack_builder* b, |
| const char* target) { |
| gpr_free(b->target); |
| b->target = gpr_strdup(target); |
| } |
| |
| const char* grpc_channel_stack_builder_get_target( |
| grpc_channel_stack_builder* b) { |
| return b->target; |
| } |
| |
| static grpc_channel_stack_builder_iterator* create_iterator_at_filter_node( |
| grpc_channel_stack_builder* builder, filter_node* node) { |
| grpc_channel_stack_builder_iterator* it = |
| (grpc_channel_stack_builder_iterator*)gpr_malloc(sizeof(*it)); |
| it->builder = builder; |
| it->node = node; |
| return it; |
| } |
| |
| void grpc_channel_stack_builder_iterator_destroy( |
| grpc_channel_stack_builder_iterator* it) { |
| gpr_free(it); |
| } |
| |
| grpc_channel_stack_builder_iterator* |
| grpc_channel_stack_builder_create_iterator_at_first( |
| grpc_channel_stack_builder* builder) { |
| return create_iterator_at_filter_node(builder, &builder->begin); |
| } |
| |
| grpc_channel_stack_builder_iterator* |
| grpc_channel_stack_builder_create_iterator_at_last( |
| grpc_channel_stack_builder* builder) { |
| return create_iterator_at_filter_node(builder, &builder->end); |
| } |
| |
| bool grpc_channel_stack_builder_iterator_is_end( |
| grpc_channel_stack_builder_iterator* iterator) { |
| return iterator->node == &iterator->builder->end; |
| } |
| |
| const char* grpc_channel_stack_builder_iterator_filter_name( |
| grpc_channel_stack_builder_iterator* iterator) { |
| if (iterator->node->filter == nullptr) return nullptr; |
| return iterator->node->filter->name; |
| } |
| |
| bool grpc_channel_stack_builder_move_next( |
| grpc_channel_stack_builder_iterator* iterator) { |
| if (iterator->node == &iterator->builder->end) return false; |
| iterator->node = iterator->node->next; |
| return true; |
| } |
| |
| bool grpc_channel_stack_builder_move_prev( |
| grpc_channel_stack_builder_iterator* iterator) { |
| if (iterator->node == &iterator->builder->begin) return false; |
| iterator->node = iterator->node->prev; |
| return true; |
| } |
| |
| grpc_channel_stack_builder_iterator* grpc_channel_stack_builder_iterator_find( |
| grpc_channel_stack_builder* builder, const char* filter_name) { |
| GPR_ASSERT(filter_name != nullptr); |
| grpc_channel_stack_builder_iterator* it = |
| grpc_channel_stack_builder_create_iterator_at_first(builder); |
| while (grpc_channel_stack_builder_move_next(it)) { |
| if (grpc_channel_stack_builder_iterator_is_end(it)) break; |
| const char* filter_name_at_it = |
| grpc_channel_stack_builder_iterator_filter_name(it); |
| if (strcmp(filter_name, filter_name_at_it) == 0) break; |
| } |
| return it; |
| } |
| |
| bool grpc_channel_stack_builder_move_prev( |
| grpc_channel_stack_builder_iterator* iterator); |
| |
| void grpc_channel_stack_builder_set_name(grpc_channel_stack_builder* builder, |
| const char* name) { |
| GPR_ASSERT(builder->name == nullptr); |
| builder->name = name; |
| } |
| |
| void grpc_channel_stack_builder_set_channel_arguments( |
| grpc_exec_ctx* exec_ctx, grpc_channel_stack_builder* builder, |
| const grpc_channel_args* args) { |
| if (builder->args != nullptr) { |
| grpc_channel_args_destroy(exec_ctx, builder->args); |
| } |
| builder->args = grpc_channel_args_copy(args); |
| } |
| |
| void grpc_channel_stack_builder_set_transport( |
| grpc_channel_stack_builder* builder, grpc_transport* transport) { |
| GPR_ASSERT(builder->transport == nullptr); |
| builder->transport = transport; |
| } |
| |
| grpc_transport* grpc_channel_stack_builder_get_transport( |
| grpc_channel_stack_builder* builder) { |
| return builder->transport; |
| } |
| |
| const grpc_channel_args* grpc_channel_stack_builder_get_channel_arguments( |
| grpc_channel_stack_builder* builder) { |
| return builder->args; |
| } |
| |
| bool grpc_channel_stack_builder_append_filter( |
| grpc_channel_stack_builder* builder, const grpc_channel_filter* filter, |
| grpc_post_filter_create_init_func post_init_func, void* user_data) { |
| grpc_channel_stack_builder_iterator* it = |
| grpc_channel_stack_builder_create_iterator_at_last(builder); |
| bool ok = grpc_channel_stack_builder_add_filter_before( |
| it, filter, post_init_func, user_data); |
| grpc_channel_stack_builder_iterator_destroy(it); |
| return ok; |
| } |
| |
| bool grpc_channel_stack_builder_remove_filter( |
| grpc_channel_stack_builder* builder, const char* filter_name) { |
| grpc_channel_stack_builder_iterator* it = |
| grpc_channel_stack_builder_iterator_find(builder, filter_name); |
| if (grpc_channel_stack_builder_iterator_is_end(it)) { |
| grpc_channel_stack_builder_iterator_destroy(it); |
| return false; |
| } |
| it->node->prev->next = it->node->next; |
| it->node->next->prev = it->node->prev; |
| gpr_free(it->node); |
| grpc_channel_stack_builder_iterator_destroy(it); |
| return true; |
| } |
| |
| bool grpc_channel_stack_builder_prepend_filter( |
| grpc_channel_stack_builder* builder, const grpc_channel_filter* filter, |
| grpc_post_filter_create_init_func post_init_func, void* user_data) { |
| grpc_channel_stack_builder_iterator* it = |
| grpc_channel_stack_builder_create_iterator_at_first(builder); |
| bool ok = grpc_channel_stack_builder_add_filter_after( |
| it, filter, post_init_func, user_data); |
| grpc_channel_stack_builder_iterator_destroy(it); |
| return ok; |
| } |
| |
| static void add_after(filter_node* before, const grpc_channel_filter* filter, |
| grpc_post_filter_create_init_func post_init_func, |
| void* user_data) { |
| filter_node* new_node = (filter_node*)gpr_malloc(sizeof(*new_node)); |
| new_node->next = before->next; |
| new_node->prev = before; |
| new_node->next->prev = new_node->prev->next = new_node; |
| new_node->filter = filter; |
| new_node->init = post_init_func; |
| new_node->init_arg = user_data; |
| } |
| |
| bool grpc_channel_stack_builder_add_filter_before( |
| grpc_channel_stack_builder_iterator* iterator, |
| const grpc_channel_filter* filter, |
| grpc_post_filter_create_init_func post_init_func, void* user_data) { |
| if (iterator->node == &iterator->builder->begin) return false; |
| add_after(iterator->node->prev, filter, post_init_func, user_data); |
| return true; |
| } |
| |
| bool grpc_channel_stack_builder_add_filter_after( |
| grpc_channel_stack_builder_iterator* iterator, |
| const grpc_channel_filter* filter, |
| grpc_post_filter_create_init_func post_init_func, void* user_data) { |
| if (iterator->node == &iterator->builder->end) return false; |
| add_after(iterator->node, filter, post_init_func, user_data); |
| return true; |
| } |
| |
| void grpc_channel_stack_builder_destroy(grpc_exec_ctx* exec_ctx, |
| grpc_channel_stack_builder* builder) { |
| filter_node* p = builder->begin.next; |
| while (p != &builder->end) { |
| filter_node* next = p->next; |
| gpr_free(p); |
| p = next; |
| } |
| if (builder->args != nullptr) { |
| grpc_channel_args_destroy(exec_ctx, builder->args); |
| } |
| gpr_free(builder->target); |
| gpr_free(builder); |
| } |
| |
| grpc_error* grpc_channel_stack_builder_finish( |
| grpc_exec_ctx* exec_ctx, grpc_channel_stack_builder* builder, |
| size_t prefix_bytes, int initial_refs, grpc_iomgr_cb_func destroy, |
| void* destroy_arg, void** result) { |
| // count the number of filters |
| size_t num_filters = 0; |
| for (filter_node* p = builder->begin.next; p != &builder->end; p = p->next) { |
| num_filters++; |
| } |
| |
| // create an array of filters |
| const grpc_channel_filter** filters = |
| (const grpc_channel_filter**)gpr_malloc(sizeof(*filters) * num_filters); |
| size_t i = 0; |
| for (filter_node* p = builder->begin.next; p != &builder->end; p = p->next) { |
| filters[i++] = p->filter; |
| } |
| |
| // calculate the size of the channel stack |
| size_t channel_stack_size = grpc_channel_stack_size(filters, num_filters); |
| |
| // allocate memory, with prefix_bytes followed by channel_stack_size |
| *result = gpr_zalloc(prefix_bytes + channel_stack_size); |
| // fetch a pointer to the channel stack |
| grpc_channel_stack* channel_stack = |
| (grpc_channel_stack*)((char*)(*result) + prefix_bytes); |
| // and initialize it |
| grpc_error* error = grpc_channel_stack_init( |
| exec_ctx, initial_refs, destroy, |
| destroy_arg == nullptr ? *result : destroy_arg, filters, num_filters, |
| builder->args, builder->transport, builder->name, channel_stack); |
| |
| if (error != GRPC_ERROR_NONE) { |
| grpc_channel_stack_destroy(exec_ctx, channel_stack); |
| gpr_free(*result); |
| *result = nullptr; |
| } else { |
| // run post-initialization functions |
| i = 0; |
| for (filter_node* p = builder->begin.next; p != &builder->end; |
| p = p->next) { |
| if (p->init != nullptr) { |
| p->init(channel_stack, grpc_channel_stack_element(channel_stack, i), |
| p->init_arg); |
| } |
| i++; |
| } |
| } |
| |
| grpc_channel_stack_builder_destroy(exec_ctx, builder); |
| gpr_free((grpc_channel_filter**)filters); |
| |
| return error; |
| } |