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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 #ifndef GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H
20 #define GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H
21 
22 #include <grpc/support/port_platform.h>
23 
24 #include <grpc/compression.h>
25 #include <grpc/grpc.h>
26 #include "src/core/lib/iomgr/socket_mutator.h"
27 
28 // Channel args are intentionally immutable, to avoid the need for locking.
29 
30 /** Copy the arguments in \a src into a new instance */
31 grpc_channel_args* grpc_channel_args_copy(const grpc_channel_args* src);
32 
33 /** Copy the arguments in \a src into a new instance, stably sorting keys */
34 grpc_channel_args* grpc_channel_args_normalize(const grpc_channel_args* src);
35 
36 /** Copy the arguments in \a src and append \a to_add. If \a to_add is NULL, it
37  * is equivalent to calling \a grpc_channel_args_copy. */
38 grpc_channel_args* grpc_channel_args_copy_and_add(const grpc_channel_args* src,
39                                                   const grpc_arg* to_add,
40                                                   size_t num_to_add);
41 
42 /** Copies the arguments in \a src except for those whose keys are in
43     \a to_remove. */
44 grpc_channel_args* grpc_channel_args_copy_and_remove(
45     const grpc_channel_args* src, const char** to_remove, size_t num_to_remove);
46 
47 /** Copies the arguments from \a src except for those whose keys are in
48     \a to_remove and appends the arguments in \a to_add. */
49 grpc_channel_args* grpc_channel_args_copy_and_add_and_remove(
50     const grpc_channel_args* src, const char** to_remove, size_t num_to_remove,
51     const grpc_arg* to_add, size_t num_to_add);
52 
53 /** Perform the union of \a a and \a b, prioritizing \a a entries */
54 grpc_channel_args* grpc_channel_args_union(const grpc_channel_args* a,
55                                            const grpc_channel_args* b);
56 
57 /** Destroy arguments created by \a grpc_channel_args_copy */
58 void grpc_channel_args_destroy(grpc_channel_args* a);
59 
60 /** Returns the compression algorithm set in \a a. */
61 grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
62     const grpc_channel_args* a);
63 
64 /** Returns a channel arg instance with compression enabled. If \a a is
65  * non-NULL, its args are copied. N.B. GRPC_COMPRESS_NONE disables compression
66  * for the channel. */
67 grpc_channel_args* grpc_channel_args_set_compression_algorithm(
68     grpc_channel_args* a, grpc_compression_algorithm algorithm);
69 
70 /** Sets the support for the given compression algorithm. By default, all
71  * compression algorithms are enabled. It's an error to disable an algorithm set
72  * by grpc_channel_args_set_compression_algorithm.
73  *
74  * Returns an instance with the updated algorithm states. The \a a pointer is
75  * modified to point to the returned instance (which may be different from the
76  * input value of \a a). */
77 grpc_channel_args* grpc_channel_args_compression_algorithm_set_state(
78     grpc_channel_args** a, grpc_compression_algorithm algorithm, int enabled);
79 
80 /** Returns the bitset representing the support state (true for enabled, false
81  * for disabled) for compression algorithms.
82  *
83  * The i-th bit of the returned bitset corresponds to the i-th entry in the
84  * grpc_compression_algorithm enum. */
85 uint32_t grpc_channel_args_compression_algorithm_get_states(
86     const grpc_channel_args* a);
87 
88 int grpc_channel_args_compare(const grpc_channel_args* a,
89                               const grpc_channel_args* b);
90 
91 /** Returns a channel arg instance with socket mutator added. The socket mutator
92  * will perform its mutate_fd method on all file descriptors used by the
93  * channel.
94  * If \a a is non-MULL, its args are copied. */
95 grpc_channel_args* grpc_channel_args_set_socket_mutator(
96     grpc_channel_args* a, grpc_socket_mutator* mutator);
97 
98 /** Returns the value of argument \a name from \a args, or NULL if not found. */
99 const grpc_arg* grpc_channel_args_find(const grpc_channel_args* args,
100                                        const char* name);
101 
102 bool grpc_channel_args_want_minimal_stack(const grpc_channel_args* args);
103 
104 typedef struct grpc_integer_options {
105   int default_value;  // Return this if value is outside of expected bounds.
106   int min_value;
107   int max_value;
108 } grpc_integer_options;
109 
110 /** Returns the value of \a arg, subject to the contraints in \a options. */
111 int grpc_channel_arg_get_integer(const grpc_arg* arg,
112                                  const grpc_integer_options options);
113 
114 /** Returns the value of \a arg if \a arg is of type GRPC_ARG_STRING.
115     Otherwise, emits a warning log, and returns nullptr.
116     If arg is nullptr, returns nullptr, and does not emit a warning. */
117 char* grpc_channel_arg_get_string(const grpc_arg* arg);
118 
119 bool grpc_channel_arg_get_bool(const grpc_arg* arg, bool default_value);
120 
121 // Helpers for creating channel args.
122 grpc_arg grpc_channel_arg_string_create(char* name, char* value);
123 grpc_arg grpc_channel_arg_integer_create(char* name, int value);
124 grpc_arg grpc_channel_arg_pointer_create(char* name, void* value,
125                                          const grpc_arg_pointer_vtable* vtable);
126 
127 // Returns a string representing channel args in human-readable form.
128 // Callers takes ownership of result.
129 char* grpc_channel_args_string(const grpc_channel_args* args);
130 
131 #endif /* GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H */
132