3 * Copyright 2015 gRPC authors.
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
9 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 #ifndef GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H
20 #define GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H
22 #include <grpc/support/port_platform.h>
24 #include <grpc/slice.h>
25 #include <grpc/slice_buffer.h>
26 #include "src/core/ext/transport/chttp2/transport/frame.h"
27 #include "src/core/lib/transport/metadata.h"
28 #include "src/core/lib/transport/metadata_batch.h"
29 #include "src/core/lib/transport/transport.h"
31 // This should be <= 8. We use 6 to save space.
32 #define GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS 6
33 #define GRPC_CHTTP2_HPACKC_NUM_VALUES (1 << GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS)
34 /* initial table size, per spec */
35 #define GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE 4096
36 /* maximum table size we'll actually use */
37 #define GRPC_CHTTP2_HPACKC_MAX_TABLE_SIZE (1024 * 1024)
39 extern grpc_core::TraceFlag grpc_http_trace;
42 uint32_t filter_elems_sum;
43 uint32_t max_table_size;
44 uint32_t max_table_elems;
45 uint32_t cap_table_elems;
46 /** if non-zero, advertise to the decoder that we'll start using a table
48 uint8_t advertise_table_size_change;
49 /** maximum number of bytes we'll use for the decode table (to guard against
50 peers ooming us by setting decode table size high) */
51 uint32_t max_usable_size;
52 /* one before the lowest usable table index */
53 uint32_t tail_remote_index;
57 /* filter tables for elems: this tables provides an approximate
58 popularity count for particular hashes, and are used to determine whether
59 a new literal should be added to the compression table or not.
60 They track a single integer that counts how often a particular value has
61 been seen. When that count reaches max (255), all values are halved. */
62 uint8_t filter_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
64 /* entry tables for keys & elems: these tables track values that have been
65 seen and *may* be in the decompressor table */
66 grpc_slice entries_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
67 grpc_mdelem entries_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
68 uint32_t indices_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
69 uint32_t indices_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
71 uint16_t* table_elem_size;
72 } grpc_chttp2_hpack_compressor;
74 void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor* c);
75 void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor* c);
76 void grpc_chttp2_hpack_compressor_set_max_table_size(
77 grpc_chttp2_hpack_compressor* c, uint32_t max_table_size);
78 void grpc_chttp2_hpack_compressor_set_max_usable_size(
79 grpc_chttp2_hpack_compressor* c, uint32_t max_table_size);
84 bool use_true_binary_metadata;
85 size_t max_frame_size;
86 grpc_transport_one_way_stats* stats;
87 } grpc_encode_header_options;
89 void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor* c,
90 grpc_mdelem** extra_headers,
91 size_t extra_headers_size,
92 grpc_metadata_batch* metadata,
93 const grpc_encode_header_options* options,
94 grpc_slice_buffer* outbuf);
96 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H */