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1 /*
2  *
3  * Copyright 2015-2016 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_GRPC_H
20 #define GRPC_GRPC_H
21 
22 #include <grpc/byte_buffer.h>
23 #include <grpc/impl/connectivity_state.h>  // IWYU pragma: export
24 #include <grpc/impl/grpc_types.h>          // IWYU pragma: export
25 #include <grpc/impl/propagation_bits.h>
26 #include <grpc/slice.h>
27 #include <grpc/status.h>
28 #include <grpc/support/port_platform.h>
29 #include <grpc/support/time.h>
30 #include <stddef.h>
31 
32 #ifdef __cplusplus
33 extern "C" {
34 #endif
35 
36 /*! \mainpage GRPC Core
37  *
38  * The GRPC Core library is a low-level library designed to be wrapped by higher
39  * level libraries. The top-level API is provided in grpc.h. Security related
40  * functionality lives in grpc_security.h.
41  */
42 
43 GRPCAPI void grpc_metadata_array_init(grpc_metadata_array* array);
44 GRPCAPI void grpc_metadata_array_destroy(grpc_metadata_array* array);
45 
46 GRPCAPI void grpc_call_details_init(grpc_call_details* details);
47 GRPCAPI void grpc_call_details_destroy(grpc_call_details* details);
48 
49 /** Initialize the grpc library.
50 
51     After it's called, a matching invocation to grpc_shutdown() is expected.
52 
53     It is not safe to call any other grpc functions before calling this.
54     (To avoid overhead, little checking is done, and some things may work. We
55     do not warrant that they will continue to do so in future revisions of this
56     library). */
57 GRPCAPI void grpc_init(void);
58 
59 /** Shut down the grpc library.
60 
61     Before it's called, there should haven been a matching invocation to
62     grpc_init().
63 
64     The last call to grpc_shutdown will initiate cleaning up of grpc library
65     internals, which can happen in another thread. Once the clean-up is done,
66     no memory is used by grpc, nor are any instructions executing within the
67     grpc library.  Prior to calling, all application owned grpc objects must
68     have been destroyed. */
69 GRPCAPI void grpc_shutdown(void);
70 
71 /** EXPERIMENTAL. Returns 1 if the grpc library has been initialized.
72     TODO(ericgribkoff) Decide if this should be promoted to non-experimental as
73     part of stabilizing the fork support API, as tracked in
74     https://github.com/grpc/grpc/issues/15334 */
75 GRPCAPI int grpc_is_initialized(void);
76 
77 /** DEPRECATED. Recommend to use grpc_shutdown only */
78 GRPCAPI void grpc_shutdown_blocking(void);
79 
80 /** Return a string representing the current version of grpc */
81 GRPCAPI const char* grpc_version_string(void);
82 
83 /** Return a string specifying what the 'g' in gRPC stands for */
84 GRPCAPI const char* grpc_g_stands_for(void);
85 
86 /** Returns the completion queue factory based on the attributes. MAY return a
87     NULL if no factory can be found */
88 GRPCAPI const grpc_completion_queue_factory*
89 grpc_completion_queue_factory_lookup(
90     const grpc_completion_queue_attributes* attributes);
91 
92 /** Helper function to create a completion queue with grpc_cq_completion_type
93     of GRPC_CQ_NEXT and grpc_cq_polling_type of GRPC_CQ_DEFAULT_POLLING */
94 GRPCAPI grpc_completion_queue* grpc_completion_queue_create_for_next(
95     void* reserved);
96 
97 /** Helper function to create a completion queue with grpc_cq_completion_type
98     of GRPC_CQ_PLUCK and grpc_cq_polling_type of GRPC_CQ_DEFAULT_POLLING */
99 GRPCAPI grpc_completion_queue* grpc_completion_queue_create_for_pluck(
100     void* reserved);
101 
102 /** Helper function to create a completion queue with grpc_cq_completion_type
103     of GRPC_CQ_CALLBACK and grpc_cq_polling_type of GRPC_CQ_DEFAULT_POLLING.
104     This function is experimental. */
105 GRPCAPI grpc_completion_queue* grpc_completion_queue_create_for_callback(
106     grpc_completion_queue_functor* shutdown_callback, void* reserved);
107 
108 /** Create a completion queue */
109 GRPCAPI grpc_completion_queue* grpc_completion_queue_create(
110     const grpc_completion_queue_factory* factory,
111     const grpc_completion_queue_attributes* attributes, void* reserved);
112 
113 /** Blocks until an event is available, the completion queue is being shut down,
114     or deadline is reached.
115 
116     Returns a grpc_event with type GRPC_QUEUE_TIMEOUT on timeout,
117     otherwise a grpc_event describing the event that occurred.
118 
119     Callers must not call grpc_completion_queue_next and
120     grpc_completion_queue_pluck simultaneously on the same completion queue. */
121 GRPCAPI grpc_event grpc_completion_queue_next(grpc_completion_queue* cq,
122                                               gpr_timespec deadline,
123                                               void* reserved);
124 
125 /** Blocks until an event with tag 'tag' is available, the completion queue is
126     being shutdown or deadline is reached.
127 
128     Returns a grpc_event with type GRPC_QUEUE_TIMEOUT on timeout,
129     otherwise a grpc_event describing the event that occurred.
130 
131     Callers must not call grpc_completion_queue_next and
132     grpc_completion_queue_pluck simultaneously on the same completion queue.
133 
134     Completion queues support a maximum of GRPC_MAX_COMPLETION_QUEUE_PLUCKERS
135     concurrently executing plucks at any time. */
136 GRPCAPI grpc_event grpc_completion_queue_pluck(grpc_completion_queue* cq,
137                                                void* tag, gpr_timespec deadline,
138                                                void* reserved);
139 
140 /** Maximum number of outstanding grpc_completion_queue_pluck executions per
141     completion queue */
142 #define GRPC_MAX_COMPLETION_QUEUE_PLUCKERS 6
143 
144 /** Begin destruction of a completion queue. Once all possible events are
145     drained then grpc_completion_queue_next will start to produce
146     GRPC_QUEUE_SHUTDOWN events only. At that point it's safe to call
147     grpc_completion_queue_destroy.
148 
149     After calling this function applications should ensure that no
150     NEW work is added to be published on this completion queue. */
151 GRPCAPI void grpc_completion_queue_shutdown(grpc_completion_queue* cq);
152 
153 /** Destroy a completion queue. The caller must ensure that the queue is
154     drained and no threads are executing grpc_completion_queue_next */
155 GRPCAPI void grpc_completion_queue_destroy(grpc_completion_queue* cq);
156 
157 /*********** EXPERIMENTAL API ************/
158 /** Initializes a thread local cache for \a cq.
159  * grpc_flush_cq_tls_cache() MUST be called on the same thread,
160  * with the same cq.
161  */
162 GRPCAPI void grpc_completion_queue_thread_local_cache_init(
163     grpc_completion_queue* cq);
164 
165 /*********** EXPERIMENTAL API ************/
166 /** Flushes the thread local cache for \a cq.
167  * Returns 1 if there was contents in the cache.  If there was an event
168  * in \a cq tls cache, its tag is placed in tag, and ok is set to the
169  * event success.
170  */
171 GRPCAPI int grpc_completion_queue_thread_local_cache_flush(
172     grpc_completion_queue* cq, void** tag, int* ok);
173 
174 /** Check the connectivity state of a channel. */
175 GRPCAPI grpc_connectivity_state grpc_channel_check_connectivity_state(
176     grpc_channel* channel, int try_to_connect);
177 
178 /** Watch for a change in connectivity state.
179     Once the channel connectivity state is different from last_observed_state,
180     tag will be enqueued on cq with success=1.
181     If deadline expires BEFORE the state is changed, tag will be enqueued on cq
182     with success=0. */
183 GRPCAPI void grpc_channel_watch_connectivity_state(
184     grpc_channel* channel, grpc_connectivity_state last_observed_state,
185     gpr_timespec deadline, grpc_completion_queue* cq, void* tag);
186 
187 /** Check whether a grpc channel supports connectivity watcher */
188 GRPCAPI int grpc_channel_support_connectivity_watcher(grpc_channel* channel);
189 
190 /** Create a call given a grpc_channel, in order to call 'method'. All
191     completions are sent to 'completion_queue'. 'method' and 'host' need only
192     live through the invocation of this function.
193     If parent_call is non-NULL, it must be a server-side call. It will be used
194     to propagate properties from the server call to this new client call,
195     depending on the value of \a propagation_mask (see propagation_bits.h for
196     possible values). */
197 GRPCAPI grpc_call* grpc_channel_create_call(
198     grpc_channel* channel, grpc_call* parent_call, uint32_t propagation_mask,
199     grpc_completion_queue* completion_queue, grpc_slice method,
200     const grpc_slice* host, gpr_timespec deadline, void* reserved);
201 
202 /** Pre-register a method/host pair on a channel.
203     method and host are not owned and must remain alive while the channel is
204     alive. */
205 GRPCAPI void* grpc_channel_register_call(grpc_channel* channel,
206                                          const char* method, const char* host,
207                                          void* reserved);
208 
209 /** Create a call given a handle returned from grpc_channel_register_call.
210     \sa grpc_channel_create_call. */
211 GRPCAPI grpc_call* grpc_channel_create_registered_call(
212     grpc_channel* channel, grpc_call* parent_call, uint32_t propagation_mask,
213     grpc_completion_queue* completion_queue, void* registered_call_handle,
214     gpr_timespec deadline, void* reserved);
215 
216 /** Allocate memory in the grpc_call arena: this memory is automatically
217     discarded at call completion */
218 GRPCAPI void* grpc_call_arena_alloc(grpc_call* call, size_t size);
219 
220 /** Start a batch of operations defined in the array ops; when complete, post a
221     completion of type 'tag' to the completion queue bound to the call.
222     The order of ops specified in the batch has no significance.
223     Only one operation of each type can be active at once in any given
224     batch.
225     If a call to grpc_call_start_batch returns GRPC_CALL_OK you must call
226     grpc_completion_queue_next or grpc_completion_queue_pluck on the completion
227     queue associated with 'call' for work to be performed. If a call to
228     grpc_call_start_batch returns any value other than GRPC_CALL_OK it is
229     guaranteed that no state associated with 'call' is changed and it is not
230     appropriate to call grpc_completion_queue_next or
231     grpc_completion_queue_pluck consequent to the failed grpc_call_start_batch
232     call.
233     If a call to grpc_call_start_batch with an empty batch returns
234     GRPC_CALL_OK, the tag is put in the completion queue immediately.
235     THREAD SAFETY: access to grpc_call_start_batch in multi-threaded environment
236     needs to be synchronized. As an optimization, you may synchronize batches
237     containing just send operations independently from batches containing just
238     receive operations. Access to grpc_call_start_batch with an empty batch is
239     thread-compatible. */
240 GRPCAPI grpc_call_error grpc_call_start_batch(grpc_call* call,
241                                               const grpc_op* ops, size_t nops,
242                                               void* tag, void* reserved);
243 
244 /** Returns a newly allocated string representing the endpoint to which this
245     call is communicating with. The string is in the uri format accepted by
246     grpc_channel_create.
247     The returned string should be disposed of with gpr_free().
248 
249     WARNING: this value is never authenticated or subject to any security
250     related code. It must not be used for any authentication related
251     functionality. Instead, use grpc_auth_context. */
252 GRPCAPI char* grpc_call_get_peer(grpc_call* call);
253 
254 struct census_context;
255 
256 /** Set census context for a call; Must be called before first call to
257    grpc_call_start_batch(). */
258 GRPCAPI void grpc_census_call_set_context(grpc_call* call,
259                                           struct census_context* context);
260 
261 /** Retrieve the calls current census context. */
262 GRPCAPI struct census_context* grpc_census_call_get_context(grpc_call* call);
263 
264 /** Return a newly allocated string representing the target a channel was
265     created for. */
266 GRPCAPI char* grpc_channel_get_target(grpc_channel* channel);
267 
268 /** Request info about the channel.
269     \a channel_info indicates what information is being requested and
270     how that information will be returned.
271     \a channel_info is owned by the caller. */
272 GRPCAPI void grpc_channel_get_info(grpc_channel* channel,
273                                    const grpc_channel_info* channel_info);
274 
275 /** EXPERIMENTAL.  Resets the channel's connect backoff.
276     TODO(roth): When we see whether this proves useful, either promote
277     to non-experimental or remove it. */
278 GRPCAPI void grpc_channel_reset_connect_backoff(grpc_channel* channel);
279 
280 /** --- grpc_channel_credentials object. ---
281 
282    A channel credentials object represents a way to authenticate a client on a
283    channel. Different types of channel credentials are declared in
284    grpc_security.h. */
285 
286 typedef struct grpc_channel_credentials grpc_channel_credentials;
287 
288 /** Releases a channel credentials object.
289    The creator of the credentials object is responsible for its release. */
290 
291 GRPCAPI void grpc_channel_credentials_release(grpc_channel_credentials* creds);
292 
293 /** --- grpc_server_credentials object. ---
294 
295    A server credentials object represents a way to authenticate a server.
296    Different types of server credentials are declared in grpc_security.h. */
297 
298 typedef struct grpc_server_credentials grpc_server_credentials;
299 
300 /** Releases a server_credentials object.
301    The creator of the server_credentials object is responsible for its release.
302    */
303 GRPCAPI void grpc_server_credentials_release(grpc_server_credentials* creds);
304 
305 /** Creates a secure channel using the passed-in credentials. Additional
306     channel level configuration MAY be provided by grpc_channel_args, though
307     the expectation is that most clients will want to simply pass NULL. The
308     user data in 'args' need only live through the invocation of this function.
309     However, if any args of the 'pointer' type are passed, then the referenced
310     vtable must be maintained by the caller until grpc_channel_destroy
311     terminates. See grpc_channel_args definition for more on this. */
312 GRPCAPI grpc_channel* grpc_channel_create(const char* target,
313                                           grpc_channel_credentials* creds,
314                                           const grpc_channel_args* args);
315 
316 /** Create a lame client: this client fails every operation attempted on it. */
317 GRPCAPI grpc_channel* grpc_lame_client_channel_create(
318     const char* target, grpc_status_code error_code, const char* error_message);
319 
320 /** Close and destroy a grpc channel */
321 GRPCAPI void grpc_channel_destroy(grpc_channel* channel);
322 
323 /** Error handling for grpc_call
324    Most grpc_call functions return a grpc_error. If the error is not GRPC_OK
325    then the operation failed due to some unsatisfied precondition.
326    If a grpc_call fails, it's guaranteed that no change to the call state
327    has been made. */
328 
329 /** Cancel an RPC.
330     Can be called multiple times, from any thread.
331     THREAD-SAFETY grpc_call_cancel and grpc_call_cancel_with_status
332     are thread-safe, and can be called at any point before grpc_call_unref
333     is called.*/
334 GRPCAPI grpc_call_error grpc_call_cancel(grpc_call* call, void* reserved);
335 
336 /** Cancel an RPC.
337     Can be called multiple times, from any thread.
338     If a status has not been received for the call, set it to the status code
339     and description passed in.
340     Importantly, this function does not send status nor description to the
341     remote endpoint.
342     Note that \a description doesn't need be a static string.
343     It doesn't need to be alive after the call to
344     grpc_call_cancel_with_status completes.
345     */
346 GRPCAPI grpc_call_error grpc_call_cancel_with_status(grpc_call* call,
347                                                      grpc_status_code status,
348                                                      const char* description,
349                                                      void* reserved);
350 
351 /* Returns whether or not the call's receive message operation failed because of
352  * an error (as opposed to a graceful end-of-stream) */
353 GRPCAPI int grpc_call_failed_before_recv_message(const grpc_call* c);
354 
355 /** Ref a call.
356     THREAD SAFETY: grpc_call_ref is thread-compatible */
357 GRPCAPI void grpc_call_ref(grpc_call* call);
358 
359 /** Unref a call.
360     THREAD SAFETY: grpc_call_unref is thread-compatible */
361 GRPCAPI void grpc_call_unref(grpc_call* call);
362 
363 typedef struct grpc_call_credentials grpc_call_credentials;
364 
365 /** Sets a credentials to a call. Can only be called on the client side before
366    grpc_call_start_batch. */
367 GRPCAPI grpc_call_error grpc_call_set_credentials(grpc_call* call,
368                                                   grpc_call_credentials* creds);
369 
370 /** Request notification of a new call.
371     Once a call is received, a notification tagged with \a tag_new is added to
372     \a cq_for_notification. \a call, \a details and \a request_metadata are
373     updated with the appropriate call information. \a cq_bound_to_call is bound
374     to \a call, and batch operation notifications for that call will be posted
375     to \a cq_bound_to_call.
376     Note that \a cq_for_notification must have been registered to the server via
377     \a grpc_server_register_completion_queue. */
378 GRPCAPI grpc_call_error grpc_server_request_call(
379     grpc_server* server, grpc_call** call, grpc_call_details* details,
380     grpc_metadata_array* request_metadata,
381     grpc_completion_queue* cq_bound_to_call,
382     grpc_completion_queue* cq_for_notification, void* tag_new);
383 
384 /** How to handle payloads for a registered method */
385 typedef enum {
386   /** Don't try to read the payload */
387   GRPC_SRM_PAYLOAD_NONE,
388   /** Read the initial payload as a byte buffer */
389   GRPC_SRM_PAYLOAD_READ_INITIAL_BYTE_BUFFER
390 } grpc_server_register_method_payload_handling;
391 
392 /** Registers a method in the server.
393     Methods to this (host, method) pair will not be reported by
394     grpc_server_request_call, but instead be reported by
395     grpc_server_request_registered_call when passed the appropriate
396     registered_method (as returned by this function).
397     Must be called before grpc_server_start.
398     Returns NULL on failure. */
399 GRPCAPI void* grpc_server_register_method(
400     grpc_server* server, const char* method, const char* host,
401     grpc_server_register_method_payload_handling payload_handling,
402     uint32_t flags);
403 
404 /** Request notification of a new pre-registered call. 'cq_for_notification'
405     must have been registered to the server via
406     grpc_server_register_completion_queue. */
407 GRPCAPI grpc_call_error grpc_server_request_registered_call(
408     grpc_server* server, void* registered_method, grpc_call** call,
409     gpr_timespec* deadline, grpc_metadata_array* request_metadata,
410     grpc_byte_buffer** optional_payload,
411     grpc_completion_queue* cq_bound_to_call,
412     grpc_completion_queue* cq_for_notification, void* tag_new);
413 
414 /** Create a server. Additional configuration for each incoming channel can
415     be specified with args. If no additional configuration is needed, args can
416     be NULL. The user data in 'args' need only live through the invocation of
417     this function. However, if any args of the 'pointer' type are passed, then
418     the referenced vtable must be maintained by the caller until
419     grpc_server_destroy terminates. See grpc_channel_args definition for more
420     on this. */
421 GRPCAPI grpc_server* grpc_server_create(const grpc_channel_args* args,
422                                         void* reserved);
423 
424 /** Register a completion queue with the server. Must be done for any
425     notification completion queue that is passed to grpc_server_request_*_call
426     and to grpc_server_shutdown_and_notify. Must be performed prior to
427     grpc_server_start. */
428 GRPCAPI void grpc_server_register_completion_queue(grpc_server* server,
429                                                    grpc_completion_queue* cq,
430                                                    void* reserved);
431 
432 // More members might be added in later, so users should take care to memset
433 // this to 0 before using it.
434 typedef struct {
435   grpc_status_code code;
436   const char* error_message;
437 } grpc_serving_status_update;
438 
439 // There might be more methods added later, so users should take care to memset
440 // this to 0 before using it.
441 typedef struct {
442   void (*on_serving_status_update)(void* user_data, const char* uri,
443                                    grpc_serving_status_update update);
444   void* user_data;
445 } grpc_server_xds_status_notifier;
446 
447 typedef struct grpc_server_config_fetcher grpc_server_config_fetcher;
448 
449 /** EXPERIMENTAL.  Creates an xDS config fetcher. */
450 GRPCAPI grpc_server_config_fetcher* grpc_server_config_fetcher_xds_create(
451     grpc_server_xds_status_notifier notifier, const grpc_channel_args* args);
452 
453 /** EXPERIMENTAL.  Destroys a config fetcher. */
454 GRPCAPI void grpc_server_config_fetcher_destroy(
455     grpc_server_config_fetcher* config_fetcher);
456 
457 /** EXPERIMENTAL.  Sets the server's config fetcher.  Takes ownership.
458     Must be called before adding ports */
459 GRPCAPI void grpc_server_set_config_fetcher(
460     grpc_server* server, grpc_server_config_fetcher* config_fetcher);
461 
462 /** Add a HTTP2 over an encrypted link over tcp listener.
463    Returns bound port number on success, 0 on failure.
464    REQUIRES: server not started */
465 GRPCAPI int grpc_server_add_http2_port(grpc_server* server, const char* addr,
466                                        grpc_server_credentials* creds);
467 
468 /** Start a server - tells all listeners to start listening */
469 GRPCAPI void grpc_server_start(grpc_server* server);
470 
471 /** Begin shutting down a server.
472     After completion, no new calls or connections will be admitted.
473     Existing calls will be allowed to complete.
474     Send a GRPC_OP_COMPLETE event when there are no more calls being serviced.
475     Shutdown is idempotent, and all tags will be notified at once if multiple
476     grpc_server_shutdown_and_notify calls are made. 'cq' must have been
477     registered to this server via grpc_server_register_completion_queue. */
478 GRPCAPI void grpc_server_shutdown_and_notify(grpc_server* server,
479                                              grpc_completion_queue* cq,
480                                              void* tag);
481 
482 /** Cancel all in-progress calls.
483     Only usable after shutdown. */
484 GRPCAPI void grpc_server_cancel_all_calls(grpc_server* server);
485 
486 /** Destroy a server.
487     Shutdown must have completed beforehand (i.e. all tags generated by
488     grpc_server_shutdown_and_notify must have been received, and at least
489     one call to grpc_server_shutdown_and_notify must have been made). */
490 GRPCAPI void grpc_server_destroy(grpc_server* server);
491 
492 /** Enable or disable a tracer.
493 
494     Tracers (usually controlled by the environment variable GRPC_TRACE)
495     allow printf-style debugging on GRPC internals, and are useful for
496     tracking down problems in the field.
497 
498     Use of this function is not strictly thread-safe, but the
499     thread-safety issues raised by it should not be of concern. */
500 GRPCAPI int grpc_tracer_set_enabled(const char* name, int enabled);
501 
502 /** Check whether a metadata key is legal (will be accepted by core) */
503 GRPCAPI int grpc_header_key_is_legal(grpc_slice slice);
504 
505 /** Check whether a non-binary metadata value is legal (will be accepted by
506     core) */
507 GRPCAPI int grpc_header_nonbin_value_is_legal(grpc_slice slice);
508 
509 /** Check whether a metadata key corresponds to a binary value */
510 GRPCAPI int grpc_is_binary_header(grpc_slice slice);
511 
512 /** Convert grpc_call_error values to a string */
513 GRPCAPI const char* grpc_call_error_to_string(grpc_call_error error);
514 
515 /** Create a buffer pool */
516 GRPCAPI grpc_resource_quota* grpc_resource_quota_create(const char* trace_name);
517 
518 /** Add a reference to a buffer pool */
519 GRPCAPI void grpc_resource_quota_ref(grpc_resource_quota* resource_quota);
520 
521 /** Drop a reference to a buffer pool */
522 GRPCAPI void grpc_resource_quota_unref(grpc_resource_quota* resource_quota);
523 
524 /** Update the size of a buffer pool */
525 GRPCAPI void grpc_resource_quota_resize(grpc_resource_quota* resource_quota,
526                                         size_t new_size);
527 
528 /** Update the size of the maximum number of threads allowed */
529 GRPCAPI void grpc_resource_quota_set_max_threads(
530     grpc_resource_quota* resource_quota, int new_max_threads);
531 
532 /** EXPERIMENTAL.  Dumps xDS configs as a serialized ClientConfig proto.
533     The full name of the proto is envoy.service.status.v3.ClientConfig. */
534 GRPCAPI grpc_slice grpc_dump_xds_configs(void);
535 
536 /** Fetch a vtable for a grpc_channel_arg that points to a grpc_resource_quota
537  */
538 GRPCAPI const grpc_arg_pointer_vtable* grpc_resource_quota_arg_vtable(void);
539 
540 /************* CHANNELZ API *************/
541 /** Channelz is under active development. The following APIs will see some
542     churn as the feature is implemented. This comment will be removed once
543     channelz is officially supported, and these APIs become stable. For now
544     you may track the progress by following this github issue:
545     https://github.com/grpc/grpc/issues/15340
546 
547     the following APIs return allocated JSON strings that match the response
548     objects from the channelz proto, found here:
549     https://github.com/grpc/grpc/blob/master/src/proto/grpc/channelz/channelz.proto.
550 
551     For easy conversion to protobuf, The JSON is formatted according to:
552     https://developers.google.com/protocol-buffers/docs/proto3#json. */
553 
554 /* Gets all root channels (i.e. channels the application has directly
555    created). This does not include subchannels nor non-top level channels.
556    The returned string is allocated and must be freed by the application. */
557 GRPCAPI char* grpc_channelz_get_top_channels(intptr_t start_channel_id);
558 
559 /* Gets all servers that exist in the process. */
560 GRPCAPI char* grpc_channelz_get_servers(intptr_t start_server_id);
561 
562 /* Returns a single Server, or else a NOT_FOUND code. */
563 GRPCAPI char* grpc_channelz_get_server(intptr_t server_id);
564 
565 /* Gets all server sockets that exist in the server. */
566 GRPCAPI char* grpc_channelz_get_server_sockets(intptr_t server_id,
567                                                intptr_t start_socket_id,
568                                                intptr_t max_results);
569 
570 /* Returns a single Channel, or else a NOT_FOUND code. The returned string
571    is allocated and must be freed by the application. */
572 GRPCAPI char* grpc_channelz_get_channel(intptr_t channel_id);
573 
574 /* Returns a single Subchannel, or else a NOT_FOUND code. The returned string
575    is allocated and must be freed by the application. */
576 GRPCAPI char* grpc_channelz_get_subchannel(intptr_t subchannel_id);
577 
578 /* Returns a single Socket, or else a NOT_FOUND code. The returned string
579    is allocated and must be freed by the application. */
580 GRPCAPI char* grpc_channelz_get_socket(intptr_t socket_id);
581 
582 /**
583  * EXPERIMENTAL - Subject to change.
584  * Fetch a vtable for grpc_channel_arg that points to
585  * grpc_authorization_policy_provider.
586  */
587 GRPCAPI const grpc_arg_pointer_vtable*
588 grpc_authorization_policy_provider_arg_vtable(void);
589 
590 #ifdef __cplusplus
591 }
592 #endif
593 
594 #endif /* GRPC_GRPC_H */
595