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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/support/port_platform.h>
23 
24 #include <stddef.h>
25 
26 #include <grpc/byte_buffer.h>
27 #include <grpc/impl/connectivity_state.h>  // IWYU pragma: export
28 #include <grpc/impl/grpc_types.h>          // IWYU pragma: export
29 #include <grpc/impl/propagation_bits.h>
30 #include <grpc/slice.h>
31 #include <grpc/status.h>
32 #include <grpc/support/time.h>
33 
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37 
38 /*! \mainpage GRPC Core
39  *
40  * The GRPC Core library is a low-level library designed to be wrapped by higher
41  * level libraries. The top-level API is provided in grpc.h. Security related
42  * functionality lives in grpc_security.h.
43  */
44 
45 GRPCAPI void grpc_metadata_array_init(grpc_metadata_array* array);
46 GRPCAPI void grpc_metadata_array_destroy(grpc_metadata_array* array);
47 
48 GRPCAPI void grpc_call_details_init(grpc_call_details* details);
49 GRPCAPI void grpc_call_details_destroy(grpc_call_details* details);
50 
51 /** Initialize the grpc library.
52 
53     After it's called, a matching invocation to grpc_shutdown() is expected.
54 
55     It is not safe to call any other grpc functions before calling this.
56     (To avoid overhead, little checking is done, and some things may work. We
57     do not warrant that they will continue to do so in future revisions of this
58     library). */
59 GRPCAPI void grpc_init(void);
60 
61 /** Shut down the grpc library.
62 
63     Before it's called, there should haven been a matching invocation to
64     grpc_init().
65 
66     The last call to grpc_shutdown will initiate cleaning up of grpc library
67     internals, which can happen in another thread. Once the clean-up is done,
68     no memory is used by grpc, nor are any instructions executing within the
69     grpc library.  Prior to calling, all application owned grpc objects must
70     have been destroyed. */
71 GRPCAPI void grpc_shutdown(void);
72 
73 /** EXPERIMENTAL. Returns 1 if the grpc library has been initialized.
74     TODO(ericgribkoff) Decide if this should be promoted to non-experimental as
75     part of stabilizing the fork support API, as tracked in
76     https://github.com/grpc/grpc/issues/15334 */
77 GRPCAPI int grpc_is_initialized(void);
78 
79 /** DEPRECATED. Recommend to use grpc_shutdown only */
80 GRPCAPI void grpc_shutdown_blocking(void);
81 
82 /** Return a string representing the current version of grpc */
83 GRPCAPI const char* grpc_version_string(void);
84 
85 /** Return a string specifying what the 'g' in gRPC stands for */
86 GRPCAPI const char* grpc_g_stands_for(void);
87 
88 /** Returns the completion queue factory based on the attributes. MAY return a
89     NULL if no factory can be found */
90 GRPCAPI const grpc_completion_queue_factory*
91 grpc_completion_queue_factory_lookup(
92     const grpc_completion_queue_attributes* attributes);
93 
94 /** Helper function to create a completion queue with grpc_cq_completion_type
95     of GRPC_CQ_NEXT and grpc_cq_polling_type of GRPC_CQ_DEFAULT_POLLING */
96 GRPCAPI grpc_completion_queue* grpc_completion_queue_create_for_next(
97     void* reserved);
98 
99 /** Helper function to create a completion queue with grpc_cq_completion_type
100     of GRPC_CQ_PLUCK and grpc_cq_polling_type of GRPC_CQ_DEFAULT_POLLING */
101 GRPCAPI grpc_completion_queue* grpc_completion_queue_create_for_pluck(
102     void* reserved);
103 
104 /** Helper function to create a completion queue with grpc_cq_completion_type
105     of GRPC_CQ_CALLBACK and grpc_cq_polling_type of GRPC_CQ_DEFAULT_POLLING.
106     This function is experimental. */
107 GRPCAPI grpc_completion_queue* grpc_completion_queue_create_for_callback(
108     grpc_completion_queue_functor* shutdown_callback, void* reserved);
109 
110 /** Create a completion queue */
111 GRPCAPI grpc_completion_queue* grpc_completion_queue_create(
112     const grpc_completion_queue_factory* factory,
113     const grpc_completion_queue_attributes* attributes, void* reserved);
114 
115 /** Blocks until an event is available, the completion queue is being shut down,
116     or deadline is reached.
117 
118     Returns a grpc_event with type GRPC_QUEUE_TIMEOUT on timeout,
119     otherwise a grpc_event describing the event that occurred.
120 
121     Callers must not call grpc_completion_queue_next and
122     grpc_completion_queue_pluck simultaneously on the same completion queue. */
123 GRPCAPI grpc_event grpc_completion_queue_next(grpc_completion_queue* cq,
124                                               gpr_timespec deadline,
125                                               void* reserved);
126 
127 /** Blocks until an event with tag 'tag' is available, the completion queue is
128     being shutdown or deadline is reached.
129 
130     Returns a grpc_event with type GRPC_QUEUE_TIMEOUT on timeout,
131     otherwise a grpc_event describing the event that occurred.
132 
133     Callers must not call grpc_completion_queue_next and
134     grpc_completion_queue_pluck simultaneously on the same completion queue.
135 
136     Completion queues support a maximum of GRPC_MAX_COMPLETION_QUEUE_PLUCKERS
137     concurrently executing plucks at any time. */
138 GRPCAPI grpc_event grpc_completion_queue_pluck(grpc_completion_queue* cq,
139                                                void* tag, gpr_timespec deadline,
140                                                void* reserved);
141 
142 /** Maximum number of outstanding grpc_completion_queue_pluck executions per
143     completion queue */
144 #define GRPC_MAX_COMPLETION_QUEUE_PLUCKERS 6
145 
146 /** Begin destruction of a completion queue. Once all possible events are
147     drained then grpc_completion_queue_next will start to produce
148     GRPC_QUEUE_SHUTDOWN events only. At that point it's safe to call
149     grpc_completion_queue_destroy.
150 
151     After calling this function applications should ensure that no
152     NEW work is added to be published on this completion queue. */
153 GRPCAPI void grpc_completion_queue_shutdown(grpc_completion_queue* cq);
154 
155 /** Destroy a completion queue. The caller must ensure that the queue is
156     drained and no threads are executing grpc_completion_queue_next */
157 GRPCAPI void grpc_completion_queue_destroy(grpc_completion_queue* cq);
158 
159 /*********** EXPERIMENTAL API ************/
160 /** Initializes a thread local cache for \a cq.
161  * grpc_flush_cq_tls_cache() MUST be called on the same thread,
162  * with the same cq.
163  */
164 GRPCAPI void grpc_completion_queue_thread_local_cache_init(
165     grpc_completion_queue* cq);
166 
167 /*********** EXPERIMENTAL API ************/
168 /** Flushes the thread local cache for \a cq.
169  * Returns 1 if there was contents in the cache.  If there was an event
170  * in \a cq tls cache, its tag is placed in tag, and ok is set to the
171  * event success.
172  */
173 GRPCAPI int grpc_completion_queue_thread_local_cache_flush(
174     grpc_completion_queue* cq, void** tag, int* ok);
175 
176 /** Check the connectivity state of a channel. */
177 GRPCAPI grpc_connectivity_state grpc_channel_check_connectivity_state(
178     grpc_channel* channel, int try_to_connect);
179 
180 /** Number of active "external connectivity state watchers" attached to a
181  * channel.
182  * Useful for testing. **/
183 GRPCAPI int grpc_channel_num_external_connectivity_watchers(
184     grpc_channel* channel);
185 
186 /** Watch for a change in connectivity state.
187     Once the channel connectivity state is different from last_observed_state,
188     tag will be enqueued on cq with success=1.
189     If deadline expires BEFORE the state is changed, tag will be enqueued on cq
190     with success=0. */
191 GRPCAPI void grpc_channel_watch_connectivity_state(
192     grpc_channel* channel, grpc_connectivity_state last_observed_state,
193     gpr_timespec deadline, grpc_completion_queue* cq, void* tag);
194 
195 /** Check whether a grpc channel supports connectivity watcher */
196 GRPCAPI int grpc_channel_support_connectivity_watcher(grpc_channel* channel);
197 
198 /** Create a call given a grpc_channel, in order to call 'method'. All
199     completions are sent to 'completion_queue'. 'method' and 'host' need only
200     live through the invocation of this function.
201     If parent_call is non-NULL, it must be a server-side call. It will be used
202     to propagate properties from the server call to this new client call,
203     depending on the value of \a propagation_mask (see propagation_bits.h for
204     possible values). */
205 GRPCAPI grpc_call* grpc_channel_create_call(
206     grpc_channel* channel, grpc_call* parent_call, uint32_t propagation_mask,
207     grpc_completion_queue* completion_queue, grpc_slice method,
208     const grpc_slice* host, gpr_timespec deadline, void* reserved);
209 
210 /** Pre-register a method/host pair on a channel.
211     method and host are not owned and must remain alive while the channel is
212     alive. */
213 GRPCAPI void* grpc_channel_register_call(grpc_channel* channel,
214                                          const char* method, const char* host,
215                                          void* reserved);
216 
217 /** Create a call given a handle returned from grpc_channel_register_call.
218     \sa grpc_channel_create_call. */
219 GRPCAPI grpc_call* grpc_channel_create_registered_call(
220     grpc_channel* channel, grpc_call* parent_call, uint32_t propagation_mask,
221     grpc_completion_queue* completion_queue, void* registered_call_handle,
222     gpr_timespec deadline, void* reserved);
223 
224 /** Allocate memory in the grpc_call arena: this memory is automatically
225     discarded at call completion */
226 GRPCAPI void* grpc_call_arena_alloc(grpc_call* call, size_t size);
227 
228 /** Start a batch of operations defined in the array ops; when complete, post a
229     completion of type 'tag' to the completion queue bound to the call.
230     The order of ops specified in the batch has no significance.
231     Only one operation of each type can be active at once in any given
232     batch.
233     If a call to grpc_call_start_batch returns GRPC_CALL_OK you must call
234     grpc_completion_queue_next or grpc_completion_queue_pluck on the completion
235     queue associated with 'call' for work to be performed. If a call to
236     grpc_call_start_batch returns any value other than GRPC_CALL_OK it is
237     guaranteed that no state associated with 'call' is changed and it is not
238     appropriate to call grpc_completion_queue_next or
239     grpc_completion_queue_pluck consequent to the failed grpc_call_start_batch
240     call.
241     If a call to grpc_call_start_batch with an empty batch returns
242     GRPC_CALL_OK, the tag is put in the completion queue immediately.
243     THREAD SAFETY: access to grpc_call_start_batch in multi-threaded environment
244     needs to be synchronized. As an optimization, you may synchronize batches
245     containing just send operations independently from batches containing just
246     receive operations. Access to grpc_call_start_batch with an empty batch is
247     thread-compatible. */
248 GRPCAPI grpc_call_error grpc_call_start_batch(grpc_call* call,
249                                               const grpc_op* ops, size_t nops,
250                                               void* tag, void* reserved);
251 
252 /** Returns a newly allocated string representing the endpoint to which this
253     call is communicating with. The string is in the uri format accepted by
254     grpc_channel_create.
255     The returned string should be disposed of with gpr_free().
256 
257     WARNING: this value is never authenticated or subject to any security
258     related code. It must not be used for any authentication related
259     functionality. Instead, use grpc_auth_context. */
260 GRPCAPI char* grpc_call_get_peer(grpc_call* call);
261 
262 struct census_context;
263 
264 /** Set census context for a call; Must be called before first call to
265    grpc_call_start_batch(). */
266 GRPCAPI void grpc_census_call_set_context(grpc_call* call,
267                                           struct census_context* context);
268 
269 /** Retrieve the calls current census context. */
270 GRPCAPI struct census_context* grpc_census_call_get_context(grpc_call* call);
271 
272 /** Return a newly allocated string representing the target a channel was
273     created for. */
274 GRPCAPI char* grpc_channel_get_target(grpc_channel* channel);
275 
276 /** Request info about the channel.
277     \a channel_info indicates what information is being requested and
278     how that information will be returned.
279     \a channel_info is owned by the caller. */
280 GRPCAPI void grpc_channel_get_info(grpc_channel* channel,
281                                    const grpc_channel_info* channel_info);
282 
283 /** EXPERIMENTAL.  Resets the channel's connect backoff.
284     TODO(roth): When we see whether this proves useful, either promote
285     to non-experimental or remove it. */
286 GRPCAPI void grpc_channel_reset_connect_backoff(grpc_channel* channel);
287 
288 /** --- grpc_channel_credentials object. ---
289 
290    A channel credentials object represents a way to authenticate a client on a
291    channel. Different types of channel credentials are declared in
292    grpc_security.h. */
293 
294 typedef struct grpc_channel_credentials grpc_channel_credentials;
295 
296 /** Releases a channel credentials object.
297    The creator of the credentials object is responsible for its release. */
298 
299 GRPCAPI void grpc_channel_credentials_release(grpc_channel_credentials* creds);
300 
301 /** --- grpc_server_credentials object. ---
302 
303    A server credentials object represents a way to authenticate a server.
304    Different types of server credentials are declared in grpc_security.h. */
305 
306 typedef struct grpc_server_credentials grpc_server_credentials;
307 
308 /** Releases a server_credentials object.
309    The creator of the server_credentials object is responsible for its release.
310    */
311 GRPCAPI void grpc_server_credentials_release(grpc_server_credentials* creds);
312 
313 /** Creates a secure channel using the passed-in credentials. Additional
314     channel level configuration MAY be provided by grpc_channel_args, though
315     the expectation is that most clients will want to simply pass NULL. The
316     user data in 'args' need only live through the invocation of this function.
317     However, if any args of the 'pointer' type are passed, then the referenced
318     vtable must be maintained by the caller until grpc_channel_destroy
319     terminates. See grpc_channel_args definition for more on this. */
320 GRPCAPI grpc_channel* grpc_channel_create(const char* target,
321                                           grpc_channel_credentials* creds,
322                                           const grpc_channel_args* args);
323 
324 /** Create a lame client: this client fails every operation attempted on it. */
325 GRPCAPI grpc_channel* grpc_lame_client_channel_create(
326     const char* target, grpc_status_code error_code, const char* error_message);
327 
328 /** Close and destroy a grpc channel */
329 GRPCAPI void grpc_channel_destroy(grpc_channel* channel);
330 
331 /** Error handling for grpc_call
332    Most grpc_call functions return a grpc_error. If the error is not GRPC_OK
333    then the operation failed due to some unsatisfied precondition.
334    If a grpc_call fails, it's guaranteed that no change to the call state
335    has been made. */
336 
337 /** Cancel an RPC.
338     Can be called multiple times, from any thread.
339     THREAD-SAFETY grpc_call_cancel and grpc_call_cancel_with_status
340     are thread-safe, and can be called at any point before grpc_call_unref
341     is called.*/
342 GRPCAPI grpc_call_error grpc_call_cancel(grpc_call* call, void* reserved);
343 
344 /** Cancel an RPC.
345     Can be called multiple times, from any thread.
346     If a status has not been received for the call, set it to the status code
347     and description passed in.
348     Importantly, this function does not send status nor description to the
349     remote endpoint.
350     Note that \a description doesn't need be a static string.
351     It doesn't need to be alive after the call to
352     grpc_call_cancel_with_status completes.
353     */
354 GRPCAPI grpc_call_error grpc_call_cancel_with_status(grpc_call* call,
355                                                      grpc_status_code status,
356                                                      const char* description,
357                                                      void* reserved);
358 
359 /* Returns whether or not the call's receive message operation failed because of
360  * an error (as opposed to a graceful end-of-stream) */
361 GRPCAPI int grpc_call_failed_before_recv_message(const grpc_call* c);
362 
363 /** Ref a call.
364     THREAD SAFETY: grpc_call_ref is thread-compatible */
365 GRPCAPI void grpc_call_ref(grpc_call* call);
366 
367 /** Unref a call.
368     THREAD SAFETY: grpc_call_unref is thread-compatible */
369 GRPCAPI void grpc_call_unref(grpc_call* call);
370 
371 /** Request notification of a new call.
372     Once a call is received, a notification tagged with \a tag_new is added to
373     \a cq_for_notification. \a call, \a details and \a request_metadata are
374     updated with the appropriate call information. \a cq_bound_to_call is bound
375     to \a call, and batch operation notifications for that call will be posted
376     to \a cq_bound_to_call.
377     Note that \a cq_for_notification must have been registered to the server via
378     \a grpc_server_register_completion_queue. */
379 GRPCAPI grpc_call_error grpc_server_request_call(
380     grpc_server* server, grpc_call** call, grpc_call_details* details,
381     grpc_metadata_array* request_metadata,
382     grpc_completion_queue* cq_bound_to_call,
383     grpc_completion_queue* cq_for_notification, void* tag_new);
384 
385 /** How to handle payloads for a registered method */
386 typedef enum {
387   /** Don't try to read the payload */
388   GRPC_SRM_PAYLOAD_NONE,
389   /** Read the initial payload as a byte buffer */
390   GRPC_SRM_PAYLOAD_READ_INITIAL_BYTE_BUFFER
391 } grpc_server_register_method_payload_handling;
392 
393 /** Registers a method in the server.
394     Methods to this (host, method) pair will not be reported by
395     grpc_server_request_call, but instead be reported by
396     grpc_server_request_registered_call when passed the appropriate
397     registered_method (as returned by this function).
398     Must be called before grpc_server_start.
399     Returns NULL on failure. */
400 GRPCAPI void* grpc_server_register_method(
401     grpc_server* server, const char* method, const char* host,
402     grpc_server_register_method_payload_handling payload_handling,
403     uint32_t flags);
404 
405 /** Request notification of a new pre-registered call. 'cq_for_notification'
406     must have been registered to the server via
407     grpc_server_register_completion_queue. */
408 GRPCAPI grpc_call_error grpc_server_request_registered_call(
409     grpc_server* server, void* registered_method, grpc_call** call,
410     gpr_timespec* deadline, grpc_metadata_array* request_metadata,
411     grpc_byte_buffer** optional_payload,
412     grpc_completion_queue* cq_bound_to_call,
413     grpc_completion_queue* cq_for_notification, void* tag_new);
414 
415 /** Create a server. Additional configuration for each incoming channel can
416     be specified with args. If no additional configuration is needed, args can
417     be NULL. The user data in 'args' need only live through the invocation of
418     this function. However, if any args of the 'pointer' type are passed, then
419     the referenced vtable must be maintained by the caller until
420     grpc_server_destroy terminates. See grpc_channel_args definition for more
421     on this. */
422 GRPCAPI grpc_server* grpc_server_create(const grpc_channel_args* args,
423                                         void* reserved);
424 
425 /** Register a completion queue with the server. Must be done for any
426     notification completion queue that is passed to grpc_server_request_*_call
427     and to grpc_server_shutdown_and_notify. Must be performed prior to
428     grpc_server_start. */
429 GRPCAPI void grpc_server_register_completion_queue(grpc_server* server,
430                                                    grpc_completion_queue* cq,
431                                                    void* reserved);
432 
433 // More members might be added in later, so users should take care to memset
434 // this to 0 before using it.
435 typedef struct {
436   grpc_status_code code;
437   const char* error_message;
438 } grpc_serving_status_update;
439 
440 // There might be more methods added later, so users should take care to memset
441 // this to 0 before using it.
442 typedef struct {
443   void (*on_serving_status_update)(void* user_data, const char* uri,
444                                    grpc_serving_status_update update);
445   void* user_data;
446 } grpc_server_xds_status_notifier;
447 
448 typedef struct grpc_server_config_fetcher grpc_server_config_fetcher;
449 
450 /** EXPERIMENTAL.  Creates an xDS config fetcher. */
451 GRPCAPI grpc_server_config_fetcher* grpc_server_config_fetcher_xds_create(
452     grpc_server_xds_status_notifier notifier, const grpc_channel_args* args);
453 
454 /** EXPERIMENTAL.  Destroys a config fetcher. */
455 GRPCAPI void grpc_server_config_fetcher_destroy(
456     grpc_server_config_fetcher* config_fetcher);
457 
458 /** EXPERIMENTAL.  Sets the server's config fetcher.  Takes ownership.
459     Must be called before adding ports */
460 GRPCAPI void grpc_server_set_config_fetcher(
461     grpc_server* server, grpc_server_config_fetcher* config_fetcher);
462 
463 /** Add a HTTP2 over an encrypted link over tcp listener.
464    Returns bound port number on success, 0 on failure.
465    REQUIRES: server not started */
466 GRPCAPI int grpc_server_add_http2_port(grpc_server* server, const char* addr,
467                                        grpc_server_credentials* creds);
468 
469 /** Start a server - tells all listeners to start listening */
470 GRPCAPI void grpc_server_start(grpc_server* server);
471 
472 /** Begin shutting down a server.
473     After completion, no new calls or connections will be admitted.
474     Existing calls will be allowed to complete.
475     Send a GRPC_OP_COMPLETE event when there are no more calls being serviced.
476     Shutdown is idempotent, and all tags will be notified at once if multiple
477     grpc_server_shutdown_and_notify calls are made. 'cq' must have been
478     registered to this server via grpc_server_register_completion_queue. */
479 GRPCAPI void grpc_server_shutdown_and_notify(grpc_server* server,
480                                              grpc_completion_queue* cq,
481                                              void* tag);
482 
483 /** Cancel all in-progress calls.
484     Only usable after shutdown. */
485 GRPCAPI void grpc_server_cancel_all_calls(grpc_server* server);
486 
487 /** Destroy a server.
488     Shutdown must have completed beforehand (i.e. all tags generated by
489     grpc_server_shutdown_and_notify must have been received, and at least
490     one call to grpc_server_shutdown_and_notify must have been made). */
491 GRPCAPI void grpc_server_destroy(grpc_server* server);
492 
493 /** Enable or disable a tracer.
494 
495     Tracers (usually controlled by the environment variable GRPC_TRACE)
496     allow printf-style debugging on GRPC internals, and are useful for
497     tracking down problems in the field.
498 
499     Use of this function is not strictly thread-safe, but the
500     thread-safety issues raised by it should not be of concern. */
501 GRPCAPI int grpc_tracer_set_enabled(const char* name, int enabled);
502 
503 /** Check whether a metadata key is legal (will be accepted by core) */
504 GRPCAPI int grpc_header_key_is_legal(grpc_slice slice);
505 
506 /** Check whether a non-binary metadata value is legal (will be accepted by
507     core) */
508 GRPCAPI int grpc_header_nonbin_value_is_legal(grpc_slice slice);
509 
510 /** Check whether a metadata key corresponds to a binary value */
511 GRPCAPI int grpc_is_binary_header(grpc_slice slice);
512 
513 /** Convert grpc_call_error values to a string */
514 GRPCAPI const char* grpc_call_error_to_string(grpc_call_error error);
515 
516 /** Create a buffer pool */
517 GRPCAPI grpc_resource_quota* grpc_resource_quota_create(const char* trace_name);
518 
519 /** Add a reference to a buffer pool */
520 GRPCAPI void grpc_resource_quota_ref(grpc_resource_quota* resource_quota);
521 
522 /** Drop a reference to a buffer pool */
523 GRPCAPI void grpc_resource_quota_unref(grpc_resource_quota* resource_quota);
524 
525 /** Update the size of a buffer pool */
526 GRPCAPI void grpc_resource_quota_resize(grpc_resource_quota* resource_quota,
527                                         size_t new_size);
528 
529 /** Update the size of the maximum number of threads allowed */
530 GRPCAPI void grpc_resource_quota_set_max_threads(
531     grpc_resource_quota* resource_quota, int new_max_threads);
532 
533 /** EXPERIMENTAL.  Dumps xDS configs as a serialized ClientConfig proto.
534     The full name of the proto is envoy.service.status.v3.ClientConfig. */
535 GRPCAPI grpc_slice grpc_dump_xds_configs(void);
536 
537 /** Fetch a vtable for a grpc_channel_arg that points to a grpc_resource_quota
538  */
539 GRPCAPI const grpc_arg_pointer_vtable* grpc_resource_quota_arg_vtable(void);
540 
541 /************* CHANNELZ API *************/
542 /** Channelz is under active development. The following APIs will see some
543     churn as the feature is implemented. This comment will be removed once
544     channelz is officially supported, and these APIs become stable. For now
545     you may track the progress by following this github issue:
546     https://github.com/grpc/grpc/issues/15340
547 
548     the following APIs return allocated JSON strings that match the response
549     objects from the channelz proto, found here:
550     https://github.com/grpc/grpc/blob/master/src/proto/grpc/channelz/channelz.proto.
551 
552     For easy conversion to protobuf, The JSON is formatted according to:
553     https://developers.google.com/protocol-buffers/docs/proto3#json. */
554 
555 /* Gets all root channels (i.e. channels the application has directly
556    created). This does not include subchannels nor non-top level channels.
557    The returned string is allocated and must be freed by the application. */
558 GRPCAPI char* grpc_channelz_get_top_channels(intptr_t start_channel_id);
559 
560 /* Gets all servers that exist in the process. */
561 GRPCAPI char* grpc_channelz_get_servers(intptr_t start_server_id);
562 
563 /* Returns a single Server, or else a NOT_FOUND code. */
564 GRPCAPI char* grpc_channelz_get_server(intptr_t server_id);
565 
566 /* Gets all server sockets that exist in the server. */
567 GRPCAPI char* grpc_channelz_get_server_sockets(intptr_t server_id,
568                                                intptr_t start_socket_id,
569                                                intptr_t max_results);
570 
571 /* Returns a single Channel, or else a NOT_FOUND code. The returned string
572    is allocated and must be freed by the application. */
573 GRPCAPI char* grpc_channelz_get_channel(intptr_t channel_id);
574 
575 /* Returns a single Subchannel, or else a NOT_FOUND code. The returned string
576    is allocated and must be freed by the application. */
577 GRPCAPI char* grpc_channelz_get_subchannel(intptr_t subchannel_id);
578 
579 /* Returns a single Socket, or else a NOT_FOUND code. The returned string
580    is allocated and must be freed by the application. */
581 GRPCAPI char* grpc_channelz_get_socket(intptr_t socket_id);
582 
583 /**
584  * EXPERIMENTAL - Subject to change.
585  * Fetch a vtable for grpc_channel_arg that points to
586  * grpc_authorization_policy_provider.
587  */
588 GRPCAPI const grpc_arg_pointer_vtable*
589 grpc_authorization_policy_provider_arg_vtable(void);
590 
591 #ifdef __cplusplus
592 }
593 #endif
594 
595 #endif /* GRPC_GRPC_H */
596