src/core/lib/iomgr/iomgr_posix_cfstream.cc

   1 /*
   2  *
   3  * Copyright 2015 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 /// CFStream is build-enabled on iOS by default and disabled by default on other
  20 /// platforms (see port_platform.h). To enable CFStream build on another
  21 /// platform, the users need to define macro "GRPC_CFSTREAM=1" when building
  22 /// gRPC.
  23 ///
  24 /// When CFStream is to be built (either by default on iOS or by macro on other
  25 /// platforms), the users can disable CFStream with environment variable
  26 /// "grpc_cfstream=0". This will let gRPC to fallback to use POSIX sockets. In
  27 /// addition, the users may choose to use an alternative CFRunLoop based pollset
  28 /// "ev_apple" by setting environment variable "GRPC_CFSTREAM_RUN_LOOP=1". This
  29 /// pollset resolves a bug from Apple when CFStream streams dispatch events to
  30 /// dispatch queues. The caveat of this pollset is that users may not be able to
  31 /// run a gRPC server in the same process.
  32
  33 #include <grpc/support/port_platform.h>
  34
  35 #include "src/core/lib/iomgr/port.h"
  36
  37 #ifdef GRPC_CFSTREAM_IOMGR
  38
  39 #include "src/core/lib/debug/trace.h"
  40 #include "src/core/lib/iomgr/ev_apple.h"
  41 #include "src/core/lib/iomgr/ev_posix.h"
  42 #include "src/core/lib/iomgr/iomgr_internal.h"
  43 #include "src/core/lib/iomgr/resolve_address.h"
  44 #include "src/core/lib/iomgr/tcp_client.h"
  45 #include "src/core/lib/iomgr/tcp_posix.h"
  46 #include "src/core/lib/iomgr/tcp_server.h"
  47 #include "src/core/lib/iomgr/timer.h"
  48
  49 static const char* grpc_cfstream_env_var = "grpc_cfstream";
  50 static const char* grpc_cfstream_run_loop_env_var = "GRPC_CFSTREAM_RUN_LOOP";
  51
  52 extern grpc_tcp_server_vtable grpc_posix_tcp_server_vtable;
  53 extern grpc_tcp_client_vtable grpc_posix_tcp_client_vtable;
  54 extern grpc_tcp_client_vtable grpc_cfstream_client_vtable;
  55 extern grpc_timer_vtable grpc_generic_timer_vtable;
  56 extern grpc_pollset_vtable grpc_posix_pollset_vtable;
  57 extern grpc_pollset_set_vtable grpc_posix_pollset_set_vtable;
  58 extern grpc_address_resolver_vtable grpc_posix_resolver_vtable;
  59
  60 static void apple_iomgr_platform_init(void) { grpc_pollset_global_init(); }
  61
  62 static void apple_iomgr_platform_flush(void) {}
  63
  64 static void apple_iomgr_platform_shutdown(void) {
  65   grpc_pollset_global_shutdown();
  66 }
  67
  68 static void apple_iomgr_platform_shutdown_background_closure(void) {}
  69
  70 static bool apple_iomgr_platform_is_any_background_poller_thread(void) {
  71   return false;
  72 }
  73
  74 static bool apple_iomgr_platform_add_closure_to_background_poller(
  75     grpc_closure* closure, grpc_error* error) {
  76   return false;
  77 }
  78
  79 static grpc_iomgr_platform_vtable apple_vtable = {
  80     apple_iomgr_platform_init,
  81     apple_iomgr_platform_flush,
  82     apple_iomgr_platform_shutdown,
  83     apple_iomgr_platform_shutdown_background_closure,
  84     apple_iomgr_platform_is_any_background_poller_thread,
  85     apple_iomgr_platform_add_closure_to_background_poller};
  86
  87 static void iomgr_platform_init(void) {
  88   grpc_wakeup_fd_global_init();
  89   grpc_event_engine_init();
  90 }
  91
  92 static void iomgr_platform_flush(void) {}
  93
  94 static void iomgr_platform_shutdown(void) {
  95   grpc_event_engine_shutdown();
  96   grpc_wakeup_fd_global_destroy();
  97 }
  98
  99 static void iomgr_platform_shutdown_background_closure(void) {
 100   grpc_shutdown_background_closure();
 101 }
 102
 103 static bool iomgr_platform_is_any_background_poller_thread(void) {
 104   return grpc_is_any_background_poller_thread();
 105 }
 106
 107 static bool iomgr_platform_add_closure_to_background_poller(
 108     grpc_closure* closure, grpc_error* error) {
 109   return grpc_add_closure_to_background_poller(closure, error);
 110 }
 111
 112 static grpc_iomgr_platform_vtable vtable = {
 113     iomgr_platform_init,
 114     iomgr_platform_flush,
 115     iomgr_platform_shutdown,
 116     iomgr_platform_shutdown_background_closure,
 117     iomgr_platform_is_any_background_poller_thread,
 118     iomgr_platform_add_closure_to_background_poller};
 119
 120 void grpc_set_default_iomgr_platform() {
 121   char* enable_cfstream_str = getenv(grpc_cfstream_env_var);
 122   bool enable_cfstream =
 123       enable_cfstream_str == nullptr || enable_cfstream_str[0] != '0';
 124   char* enable_cfstream_run_loop_str = getenv(grpc_cfstream_run_loop_env_var);
 125   // CFStream run-loop is disabled by default. The user has to enable it
 126   // explicitly with environment variable.
 127   bool enable_cfstream_run_loop = enable_cfstream_run_loop_str != nullptr &&
 128                                   enable_cfstream_run_loop_str[0] == '1';
 129   if (!enable_cfstream) {
 130     // Use POSIX sockets for both client and server
 131     grpc_set_tcp_client_impl(&grpc_posix_tcp_client_vtable);
 132     grpc_set_tcp_server_impl(&grpc_posix_tcp_server_vtable);
 133     grpc_set_pollset_vtable(&grpc_posix_pollset_vtable);
 134     grpc_set_pollset_set_vtable(&grpc_posix_pollset_set_vtable);
 135     grpc_set_iomgr_platform_vtable(&vtable);
 136   } else if (enable_cfstream && !enable_cfstream_run_loop) {
 137     // Use CFStream with dispatch queue for client; use POSIX sockets for server
 138     grpc_set_tcp_client_impl(&grpc_cfstream_client_vtable);
 139     grpc_set_tcp_server_impl(&grpc_posix_tcp_server_vtable);
 140     grpc_set_pollset_vtable(&grpc_posix_pollset_vtable);
 141     grpc_set_pollset_set_vtable(&grpc_posix_pollset_set_vtable);
 142     grpc_set_iomgr_platform_vtable(&vtable);
 143   } else {
 144     // Use CFStream with CFRunLoop for client; server not supported
 145     grpc_set_tcp_client_impl(&grpc_cfstream_client_vtable);
 146     grpc_set_pollset_vtable(&grpc_apple_pollset_vtable);
 147     grpc_set_pollset_set_vtable(&grpc_apple_pollset_set_vtable);
 148     grpc_set_iomgr_platform_vtable(&apple_vtable);
 149   }
 150   grpc_set_timer_impl(&grpc_generic_timer_vtable);
 151   grpc_set_resolver_impl(&grpc_posix_resolver_vtable);
 152 }
 153
 154 bool grpc_iomgr_run_in_background() {
 155   char* enable_cfstream_str = getenv(grpc_cfstream_env_var);
 156   bool enable_cfstream =
 157       enable_cfstream_str == nullptr || enable_cfstream_str[0] != '0';
 158   char* enable_cfstream_run_loop_str = getenv(grpc_cfstream_run_loop_env_var);
 159   // CFStream run-loop is disabled by default. The user has to enable it
 160   // explicitly with environment variable.
 161   bool enable_cfstream_run_loop = enable_cfstream_run_loop_str != nullptr &&
 162                                   enable_cfstream_run_loop_str[0] == '1';
 163   if (enable_cfstream && enable_cfstream_run_loop) {
 164     return false;
 165   } else {
 166     return grpc_event_engine_run_in_background();
 167   }
 168 }
 169
 170 #endif /* GRPC_CFSTREAM_IOMGR */