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      1 /*
      2  *
      3  * Copyright 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_IMPL_CODEGEN_COMPRESSION_TYPES_H
     20 #define GRPC_IMPL_CODEGEN_COMPRESSION_TYPES_H
     21 
     22 #include <grpc/impl/codegen/port_platform.h>
     23 
     24 #ifdef __cplusplus
     25 extern "C" {
     26 #endif
     27 
     28 /** To be used as initial metadata key for the request of a concrete compression
     29  * algorithm */
     30 #define GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY \
     31   "grpc-internal-encoding-request"
     32 
     33 /** To be used in channel arguments.
     34  *
     35  * \addtogroup grpc_arg_keys
     36  * \{ */
     37 /** Default compression algorithm for the channel.
     38  * Its value is an int from the \a grpc_compression_algorithm enum. */
     39 #define GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM \
     40   "grpc.default_compression_algorithm"
     41 /** Default compression level for the channel.
     42  * Its value is an int from the \a grpc_compression_level enum. */
     43 #define GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL "grpc.default_compression_level"
     44 /** Compression algorithms supported by the channel.
     45  * Its value is a bitset (an int). Bits correspond to algorithms in \a
     46  * grpc_compression_algorithm. For example, its LSB corresponds to
     47  * GRPC_COMPRESS_NONE, the next bit to GRPC_COMPRESS_DEFLATE, etc.
     48  * Unset bits disable support for the algorithm. By default all algorithms are
     49  * supported. It's not possible to disable GRPC_COMPRESS_NONE (the attempt will
     50  * be ignored). */
     51 #define GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET \
     52   "grpc.compression_enabled_algorithms_bitset"
     53 /** \} */
     54 
     55 /** The various compression algorithms supported by gRPC */
     56 typedef enum {
     57   GRPC_COMPRESS_NONE = 0,
     58   GRPC_COMPRESS_DEFLATE,
     59   GRPC_COMPRESS_GZIP,
     60   /* EXPERIMENTAL: Stream compression is currently experimental. */
     61   GRPC_COMPRESS_STREAM_GZIP,
     62   /* TODO(ctiller): snappy */
     63   GRPC_COMPRESS_ALGORITHMS_COUNT
     64 } grpc_compression_algorithm;
     65 
     66 /** Compression levels allow a party with knowledge of its peer's accepted
     67  * encodings to request compression in an abstract way. The level-algorithm
     68  * mapping is performed internally and depends on the peer's supported
     69  * compression algorithms. */
     70 typedef enum {
     71   GRPC_COMPRESS_LEVEL_NONE = 0,
     72   GRPC_COMPRESS_LEVEL_LOW,
     73   GRPC_COMPRESS_LEVEL_MED,
     74   GRPC_COMPRESS_LEVEL_HIGH,
     75   GRPC_COMPRESS_LEVEL_COUNT
     76 } grpc_compression_level;
     77 
     78 typedef struct grpc_compression_options {
     79   /** All algs are enabled by default. This option corresponds to the channel
     80    * argument key behind \a GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET
     81    */
     82   uint32_t enabled_algorithms_bitset;
     83 
     84   /** The default compression level. It'll be used in the absence of call
     85    * specific settings. This option corresponds to the channel
     86    * argument key behind \a GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL. If present,
     87    * takes precedence over \a default_algorithm.
     88    * TODO(dgq): currently only available for server channels. */
     89   struct grpc_compression_options_default_level {
     90     int is_set;
     91     grpc_compression_level level;
     92   } default_level;
     93 
     94   /** The default message compression algorithm. It'll be used in the absence of
     95    * call specific settings. This option corresponds to the channel argument key
     96    * behind \a GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM. */
     97   struct grpc_compression_options_default_algorithm {
     98     int is_set;
     99     grpc_compression_algorithm algorithm;
    100   } default_algorithm;
    101 } grpc_compression_options;
    102 
    103 #ifdef __cplusplus
    104 }
    105 #endif
    106 
    107 #endif /* GRPC_IMPL_CODEGEN_COMPRESSION_TYPES_H */
    108