src/core/lib/compression/compression_internal.cc

   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 #include <grpc/support/port_platform.h>
  20
  21 #include "src/core/lib/compression/compression_internal.h"
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include <grpc/compression.h>
  27
  28 #include "src/core/lib/compression/algorithm_metadata.h"
  29 #include "src/core/lib/gpr/useful.h"
  30 #include "src/core/lib/slice/slice_utils.h"
  31 #include "src/core/lib/surface/api_trace.h"
  32 #include "src/core/lib/transport/static_metadata.h"
  33
  34 /* Interfaces related to MD */
  35
  36 grpc_message_compression_algorithm
  37 grpc_message_compression_algorithm_from_slice(const grpc_slice& str) {
  38   if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_IDENTITY)) {
  39     return GRPC_MESSAGE_COMPRESS_NONE;
  40   }
  41   if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_DEFLATE)) {
  42     return GRPC_MESSAGE_COMPRESS_DEFLATE;
  43   }
  44   if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_GZIP)) {
  45     return GRPC_MESSAGE_COMPRESS_GZIP;
  46   }
  47   return GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT;
  48 }
  49
  50 grpc_stream_compression_algorithm grpc_stream_compression_algorithm_from_slice(
  51     const grpc_slice& str) {
  52   if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_IDENTITY)) {
  53     return GRPC_STREAM_COMPRESS_NONE;
  54   }
  55   if (grpc_slice_eq_static_interned(str, GRPC_MDSTR_GZIP)) {
  56     return GRPC_STREAM_COMPRESS_GZIP;
  57   }
  58   return GRPC_STREAM_COMPRESS_ALGORITHMS_COUNT;
  59 }
  60
  61 grpc_mdelem grpc_message_compression_encoding_mdelem(
  62     grpc_message_compression_algorithm algorithm) {
  63   switch (algorithm) {
  64     case GRPC_MESSAGE_COMPRESS_NONE:
  65       return GRPC_MDELEM_GRPC_ENCODING_IDENTITY;
  66     case GRPC_MESSAGE_COMPRESS_DEFLATE:
  67       return GRPC_MDELEM_GRPC_ENCODING_DEFLATE;
  68     case GRPC_MESSAGE_COMPRESS_GZIP:
  69       return GRPC_MDELEM_GRPC_ENCODING_GZIP;
  70     default:
  71       break;
  72   }
  73   return GRPC_MDNULL;
  74 }
  75
  76 grpc_mdelem grpc_stream_compression_encoding_mdelem(
  77     grpc_stream_compression_algorithm algorithm) {
  78   switch (algorithm) {
  79     case GRPC_STREAM_COMPRESS_NONE:
  80       return GRPC_MDELEM_CONTENT_ENCODING_IDENTITY;
  81     case GRPC_STREAM_COMPRESS_GZIP:
  82       return GRPC_MDELEM_CONTENT_ENCODING_GZIP;
  83     default:
  84       break;
  85   }
  86   return GRPC_MDNULL;
  87 }
  88
  89 /* Interfaces performing transformation between compression algorithms and
  90  * levels. */
  91 grpc_message_compression_algorithm
  92 grpc_compression_algorithm_to_message_compression_algorithm(
  93     grpc_compression_algorithm algo) {
  94   switch (algo) {
  95     case GRPC_COMPRESS_DEFLATE:
  96       return GRPC_MESSAGE_COMPRESS_DEFLATE;
  97     case GRPC_COMPRESS_GZIP:
  98       return GRPC_MESSAGE_COMPRESS_GZIP;
  99     default:
 100       return GRPC_MESSAGE_COMPRESS_NONE;
 101   }
 102 }
 103
 104 grpc_stream_compression_algorithm
 105 grpc_compression_algorithm_to_stream_compression_algorithm(
 106     grpc_compression_algorithm algo) {
 107   switch (algo) {
 108     case GRPC_COMPRESS_STREAM_GZIP:
 109       return GRPC_STREAM_COMPRESS_GZIP;
 110     default:
 111       return GRPC_STREAM_COMPRESS_NONE;
 112   }
 113 }
 114
 115 uint32_t grpc_compression_bitset_to_message_bitset(uint32_t bitset) {
 116   return bitset & ((1u << GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT) - 1);
 117 }
 118
 119 uint32_t grpc_compression_bitset_to_stream_bitset(uint32_t bitset) {
 120   uint32_t identity = (bitset & 1u);
 121   uint32_t other_bits =
 122       (bitset >> (GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT - 1)) &
 123       ((1u << GRPC_STREAM_COMPRESS_ALGORITHMS_COUNT) - 2);
 124   return identity | other_bits;
 125 }
 126
 127 uint32_t grpc_compression_bitset_from_message_stream_compression_bitset(
 128     uint32_t message_bitset, uint32_t stream_bitset) {
 129   uint32_t offset_stream_bitset =
 130       (stream_bitset & 1u) |
 131       ((stream_bitset & (~1u)) << (GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT - 1));
 132   return message_bitset | offset_stream_bitset;
 133 }
 134
 135 int grpc_compression_algorithm_from_message_stream_compression_algorithm(
 136     grpc_compression_algorithm* algorithm,
 137     grpc_message_compression_algorithm message_algorithm,
 138     grpc_stream_compression_algorithm stream_algorithm) {
 139   if (message_algorithm != GRPC_MESSAGE_COMPRESS_NONE &&
 140       stream_algorithm != GRPC_STREAM_COMPRESS_NONE) {
 141     *algorithm = GRPC_COMPRESS_NONE;
 142     return 0;
 143   }
 144   if (message_algorithm == GRPC_MESSAGE_COMPRESS_NONE) {
 145     switch (stream_algorithm) {
 146       case GRPC_STREAM_COMPRESS_NONE:
 147         *algorithm = GRPC_COMPRESS_NONE;
 148         return 1;
 149       case GRPC_STREAM_COMPRESS_GZIP:
 150         *algorithm = GRPC_COMPRESS_STREAM_GZIP;
 151         return 1;
 152       default:
 153         *algorithm = GRPC_COMPRESS_NONE;
 154         return 0;
 155     }
 156   } else {
 157     switch (message_algorithm) {
 158       case GRPC_MESSAGE_COMPRESS_NONE:
 159         *algorithm = GRPC_COMPRESS_NONE;
 160         return 1;
 161       case GRPC_MESSAGE_COMPRESS_DEFLATE:
 162         *algorithm = GRPC_COMPRESS_DEFLATE;
 163         return 1;
 164       case GRPC_MESSAGE_COMPRESS_GZIP:
 165         *algorithm = GRPC_COMPRESS_GZIP;
 166         return 1;
 167       default:
 168         *algorithm = GRPC_COMPRESS_NONE;
 169         return 0;
 170     }
 171   }
 172 }
 173
 174 /* Interfaces for message compression. */
 175
 176 int grpc_message_compression_algorithm_name(
 177     grpc_message_compression_algorithm algorithm, const char** name) {
 178   GRPC_API_TRACE(
 179       "grpc_message_compression_algorithm_name(algorithm=%d, name=%p)", 2,
 180       ((int)algorithm, name));
 181   switch (algorithm) {
 182     case GRPC_MESSAGE_COMPRESS_NONE:
 183       *name = "identity";
 184       return 1;
 185     case GRPC_MESSAGE_COMPRESS_DEFLATE:
 186       *name = "deflate";
 187       return 1;
 188     case GRPC_MESSAGE_COMPRESS_GZIP:
 189       *name = "gzip";
 190       return 1;
 191     case GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT:
 192       return 0;
 193   }
 194   return 0;
 195 }
 196
 197 /* TODO(dgq): Add the ability to specify parameters to the individual
 198  * compression algorithms */
 199 grpc_message_compression_algorithm grpc_message_compression_algorithm_for_level(
 200     grpc_compression_level level, uint32_t accepted_encodings) {
 201   GRPC_API_TRACE("grpc_message_compression_algorithm_for_level(level=%d)", 1,
 202                  ((int)level));
 203   if (level > GRPC_COMPRESS_LEVEL_HIGH) {
 204     gpr_log(GPR_ERROR, "Unknown message compression level %d.",
 205             static_cast<int>(level));
 206     abort();
 207   }
 208
 209   const size_t num_supported =
 210       GPR_BITCOUNT(accepted_encodings) - 1; /* discard NONE */
 211   if (level == GRPC_COMPRESS_LEVEL_NONE || num_supported == 0) {
 212     return GRPC_MESSAGE_COMPRESS_NONE;
 213   }
 214
 215   GPR_ASSERT(level > 0);
 216
 217   /* Establish a "ranking" or compression algorithms in increasing order of
 218    * compression.
 219    * This is simplistic and we will probably want to introduce other dimensions
 220    * in the future (cpu/memory cost, etc). */
 221   const grpc_message_compression_algorithm algos_ranking[] = {
 222       GRPC_MESSAGE_COMPRESS_GZIP, GRPC_MESSAGE_COMPRESS_DEFLATE};
 223
 224   /* intersect algos_ranking with the supported ones keeping the ranked order */
 225   grpc_message_compression_algorithm
 226       sorted_supported_algos[GRPC_MESSAGE_COMPRESS_ALGORITHMS_COUNT];
 227   size_t algos_supported_idx = 0;
 228   for (size_t i = 0; i < GPR_ARRAY_SIZE(algos_ranking); i++) {
 229     const grpc_message_compression_algorithm alg = algos_ranking[i];
 230     for (size_t j = 0; j < num_supported; j++) {
 231       if (GPR_BITGET(accepted_encodings, alg) == 1) {
 232         /* if \a alg in supported */
 233         sorted_supported_algos[algos_supported_idx++] = alg;
 234         break;
 235       }
 236     }
 237     if (algos_supported_idx == num_supported) break;
 238   }
 239
 240   switch (level) {
 241     case GRPC_COMPRESS_LEVEL_NONE:
 242       abort(); /* should have been handled already */
 243     case GRPC_COMPRESS_LEVEL_LOW:
 244       return sorted_supported_algos[0];
 245     case GRPC_COMPRESS_LEVEL_MED:
 246       return sorted_supported_algos[num_supported / 2];
 247     case GRPC_COMPRESS_LEVEL_HIGH:
 248       return sorted_supported_algos[num_supported - 1];
 249     default:
 250       abort();
 251   };
 252 }
 253
 254 int grpc_message_compression_algorithm_parse(
 255     grpc_slice value, grpc_message_compression_algorithm* algorithm) {
 256   if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_IDENTITY)) {
 257     *algorithm = GRPC_MESSAGE_COMPRESS_NONE;
 258     return 1;
 259   } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_DEFLATE)) {
 260     *algorithm = GRPC_MESSAGE_COMPRESS_DEFLATE;
 261     return 1;
 262   } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_GZIP)) {
 263     *algorithm = GRPC_MESSAGE_COMPRESS_GZIP;
 264     return 1;
 265   } else {
 266     return 0;
 267   }
 268 }
 269
 270 /* Interfaces for stream compression. */
 271
 272 int grpc_stream_compression_algorithm_parse(
 273     grpc_slice value, grpc_stream_compression_algorithm* algorithm) {
 274   if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_IDENTITY)) {
 275     *algorithm = GRPC_STREAM_COMPRESS_NONE;
 276     return 1;
 277   } else if (grpc_slice_eq_static_interned(value, GRPC_MDSTR_GZIP)) {
 278     *algorithm = GRPC_STREAM_COMPRESS_GZIP;
 279     return 1;
 280   } else {
 281     return 0;
 282   }
 283 }