xref: /aosp_15_r20/external/grpc-grpc/include/grpcpp/impl/metadata_map.h (revision cc02d7e222339f7a4f6ba5f422e6413f4bd931f2)
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 GRPCPP_IMPL_METADATA_MAP_H
20 #define GRPCPP_IMPL_METADATA_MAP_H
21 
22 #include <map>
23 
24 #include <grpc/grpc.h>
25 #include <grpc/support/log.h>
26 #include <grpcpp/support/slice.h>
27 
28 namespace grpc {
29 
30 namespace internal {
31 
32 const char kBinaryErrorDetailsKey[] = "grpc-status-details-bin";
33 
34 class MetadataMap {
35  public:
MetadataMap()36   MetadataMap() { Setup(); }
37 
~MetadataMap()38   ~MetadataMap() { Destroy(); }
39 
GetBinaryErrorDetails()40   std::string GetBinaryErrorDetails() {
41     // if filled_, extract from the multimap for O(log(n))
42     if (filled_) {
43       auto iter = map_.find(kBinaryErrorDetailsKey);
44       if (iter != map_.end()) {
45         return std::string(iter->second.begin(), iter->second.length());
46       }
47     }
48     // if not yet filled, take the O(n) lookup to avoid allocating the
49     // multimap until it is requested.
50     // TODO(ncteisen): plumb this through core as a first class object, just
51     // like code and message.
52     else {
53       for (size_t i = 0; i < arr_.count; i++) {
54         if (strncmp(reinterpret_cast<const char*>(
55                         GRPC_SLICE_START_PTR(arr_.metadata[i].key)),
56                     kBinaryErrorDetailsKey,
57                     GRPC_SLICE_LENGTH(arr_.metadata[i].key)) == 0) {
58           return std::string(reinterpret_cast<const char*>(
59                                  GRPC_SLICE_START_PTR(arr_.metadata[i].value)),
60                              GRPC_SLICE_LENGTH(arr_.metadata[i].value));
61         }
62       }
63     }
64     return std::string();
65   }
66 
map()67   std::multimap<grpc::string_ref, grpc::string_ref>* map() {
68     FillMap();
69     return &map_;
70   }
arr()71   grpc_metadata_array* arr() { return &arr_; }
72 
Reset()73   void Reset() {
74     filled_ = false;
75     map_.clear();
76     Destroy();
77     Setup();
78   }
79 
80  private:
81   bool filled_ = false;
82   grpc_metadata_array arr_;
83   std::multimap<grpc::string_ref, grpc::string_ref> map_;
84 
Destroy()85   void Destroy() { grpc_metadata_array_destroy(&arr_); }
86 
Setup()87   void Setup() { memset(&arr_, 0, sizeof(arr_)); }
88 
FillMap()89   void FillMap() {
90     if (filled_) return;
91     filled_ = true;
92     for (size_t i = 0; i < arr_.count; i++) {
93       // TODO(yangg) handle duplicates?
94       map_.insert(std::pair<grpc::string_ref, grpc::string_ref>(
95           StringRefFromSlice(&arr_.metadata[i].key),
96           StringRefFromSlice(&arr_.metadata[i].value)));
97     }
98   }
99 };
100 }  // namespace internal
101 
102 }  // namespace grpc
103 
104 #endif  // GRPCPP_IMPL_METADATA_MAP_H
105