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1 //
2 //
3 // Copyright 2017 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_SRC_CORE_LIB_COMPRESSION_COMPRESSION_INTERNAL_H
20 #define GRPC_SRC_CORE_LIB_COMPRESSION_COMPRESSION_INTERNAL_H
21 
22 #include <grpc/support/port_platform.h>
23 
24 #include <stdint.h>
25 
26 #include <initializer_list>
27 
28 #include "absl/strings/string_view.h"
29 #include "absl/types/optional.h"
30 
31 #include <grpc/impl/compression_types.h>
32 
33 #include "src/core/lib/channel/channel_args.h"
34 #include "src/core/lib/gprpp/bitset.h"
35 #include "src/core/lib/slice/slice.h"
36 
37 namespace grpc_core {
38 
39 // Given a string naming a compression algorithm, return the corresponding enum
40 // or nullopt on error.
41 absl::optional<grpc_compression_algorithm> ParseCompressionAlgorithm(
42     absl::string_view algorithm);
43 // Convert a compression algorithm to a string. Returns nullptr if a name is not
44 // known.
45 const char* CompressionAlgorithmAsString(grpc_compression_algorithm algorithm);
46 // Retrieve the default compression algorithm from channel args, return nullopt
47 // if not found.
48 absl::optional<grpc_compression_algorithm>
49 DefaultCompressionAlgorithmFromChannelArgs(const ChannelArgs& args);
50 
51 // A set of grpc_compression_algorithm values.
52 class CompressionAlgorithmSet {
53  public:
54   // Construct from a uint32_t bitmask - bit 0 => algorithm 0, bit 1 =>
55   // algorithm 1, etc.
56   static CompressionAlgorithmSet FromUint32(uint32_t value);
57   // Locate in channel args and construct from the found value.
58   static CompressionAlgorithmSet FromChannelArgs(const ChannelArgs& args);
59   // Parse a string of comma-separated compression algorithms.
60   static CompressionAlgorithmSet FromString(absl::string_view str);
61   // Construct an empty set.
62   CompressionAlgorithmSet();
63   // Construct from a std::initializer_list of grpc_compression_algorithm
64   // values.
65   CompressionAlgorithmSet(
66       std::initializer_list<grpc_compression_algorithm> algorithms);
67 
68   // Given a compression level, choose an appropriate algorithm from this set.
69   grpc_compression_algorithm CompressionAlgorithmForLevel(
70       grpc_compression_level level) const;
71   // Return true if this set contains algorithm, false otherwise.
72   bool IsSet(grpc_compression_algorithm algorithm) const;
73   // Add algorithm to this set.
74   void Set(grpc_compression_algorithm algorithm);
75 
76   // Return a comma separated string of the algorithms in this set.
77   absl::string_view ToString() const;
78   Slice ToSlice() const;
79 
80   // Return a bitmask of the algorithms in this set.
81   uint32_t ToLegacyBitmask() const;
82 
83   bool operator==(const CompressionAlgorithmSet& other) const {
84     return set_ == other.set_;
85   }
86 
87  private:
88   BitSet<GRPC_COMPRESS_ALGORITHMS_COUNT> set_;
89 };
90 
91 grpc_compression_options CompressionOptionsFromChannelArgs(
92     const ChannelArgs& args);
93 
94 }  // namespace grpc_core
95 
96 #endif  // GRPC_SRC_CORE_LIB_COMPRESSION_COMPRESSION_INTERNAL_H
97