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 <string>
25
26 #include <grpc/grpc.h>
27
28 #include "src/core/lib/surface/channel_stack_type.h"
29
30 // Channel args are intentionally immutable, to avoid the need for locking.
31
32 /** Copy the arguments in \a src into a new instance */
33 grpc_channel_args* grpc_channel_args_copy(const grpc_channel_args* src);
34
35 /** Copy the arguments in \a src into a new instance, stably sorting keys */
36 grpc_channel_args* grpc_channel_args_normalize(const grpc_channel_args* src);
37
38 /** Copy the arguments in \a src and append \a to_add. If \a to_add is NULL, it
39 * is equivalent to calling \a grpc_channel_args_copy. */
40 grpc_channel_args* grpc_channel_args_copy_and_add(const grpc_channel_args* src,
41 const grpc_arg* to_add,
42 size_t num_to_add);
43
44 /** Copies the arguments in \a src except for those whose keys are in
45 \a to_remove. */
46 grpc_channel_args* grpc_channel_args_copy_and_remove(
47 const grpc_channel_args* src, const char** to_remove, size_t num_to_remove);
48
49 /** Copies the arguments from \a src except for those whose keys are in
50 \a to_remove and appends the arguments in \a to_add. */
51 grpc_channel_args* grpc_channel_args_copy_and_add_and_remove(
52 const grpc_channel_args* src, const char** to_remove, size_t num_to_remove,
53 const grpc_arg* to_add, size_t num_to_add);
54
55 /** Perform the union of \a a and \a b, prioritizing \a a entries */
56 grpc_channel_args* grpc_channel_args_union(const grpc_channel_args* a,
57 const grpc_channel_args* b);
58
59 /** Destroy arguments created by \a grpc_channel_args_copy */
60 void grpc_channel_args_destroy(grpc_channel_args* a);
grpc_channel_args_destroy(const grpc_channel_args * a)61 inline void grpc_channel_args_destroy(const grpc_channel_args* a) {
62 grpc_channel_args_destroy(const_cast<grpc_channel_args*>(a));
63 }
64
65 int grpc_channel_args_compare(const grpc_channel_args* a,
66 const grpc_channel_args* b);
67
68 /** Returns the value of argument \a name from \a args, or NULL if not found. */
69 const grpc_arg* grpc_channel_args_find(const grpc_channel_args* args,
70 const char* name);
71
72 bool grpc_channel_args_want_minimal_stack(const grpc_channel_args* args);
73
74 typedef struct grpc_integer_options {
75 int default_value; // Return this if value is outside of expected bounds.
76 int min_value;
77 int max_value;
78 } grpc_integer_options;
79
80 /** Returns the value of \a arg, subject to the constraints in \a options. */
81 int grpc_channel_arg_get_integer(const grpc_arg* arg,
82 const grpc_integer_options options);
83 /** Similar to the above, but needs to find the arg from \a args by the name
84 * first. */
85 int grpc_channel_args_find_integer(const grpc_channel_args* args,
86 const char* name,
87 const grpc_integer_options options);
88
89 /** Returns the value of \a arg if \a arg is of type GRPC_ARG_STRING.
90 Otherwise, emits a warning log, and returns nullptr.
91 If arg is nullptr, returns nullptr, and does not emit a warning. */
92 char* grpc_channel_arg_get_string(const grpc_arg* arg);
93 /** Similar to the above, but needs to find the arg from \a args by the name
94 * first. */
95 char* grpc_channel_args_find_string(const grpc_channel_args* args,
96 const char* name);
97 /** If \a arg is of type GRPC_ARG_INTEGER, returns true if it's non-zero.
98 * Returns \a default_value if \a arg is of other types. */
99 bool grpc_channel_arg_get_bool(const grpc_arg* arg, bool default_value);
100 /** Similar to the above, but needs to find the arg from \a args by the name
101 * first. */
102 bool grpc_channel_args_find_bool(const grpc_channel_args* args,
103 const char* name, bool default_value);
104
105 template <typename T>
grpc_channel_args_find_pointer(const grpc_channel_args * args,const char * name)106 T* grpc_channel_args_find_pointer(const grpc_channel_args* args,
107 const char* name) {
108 const grpc_arg* arg = grpc_channel_args_find(args, name);
109 if (arg == nullptr || arg->type != GRPC_ARG_POINTER) return nullptr;
110 return static_cast<T*>(arg->value.pointer.p);
111 }
112
113 // Helpers for creating channel args.
114 grpc_arg grpc_channel_arg_string_create(char* name, char* value);
115 grpc_arg grpc_channel_arg_integer_create(char* name, int value);
116 grpc_arg grpc_channel_arg_pointer_create(char* name, void* value,
117 const grpc_arg_pointer_vtable* vtable);
118
119 // Returns a string representing channel args in human-readable form.
120 std::string grpc_channel_args_string(const grpc_channel_args* args);
121
122 // Takes ownership of the old_args
123 typedef grpc_channel_args* (*grpc_channel_args_client_channel_creation_mutator)(
124 const char* target, grpc_channel_args* old_args,
125 grpc_channel_stack_type type);
126
127 // Should be called only once globaly before grpc is init'ed.
128 void grpc_channel_args_set_client_channel_creation_mutator(
129 grpc_channel_args_client_channel_creation_mutator cb);
130 // This will be called at the creation of each channel.
131 grpc_channel_args_client_channel_creation_mutator
132 grpc_channel_args_get_client_channel_creation_mutator();
133
134 #endif /* GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H */
135