diff options
Diffstat (limited to 'src/core/lib/transport/chttp2/hpack_encoder.c')
| -rw-r--r-- | src/core/lib/transport/chttp2/hpack_encoder.c | 568 |
1 files changed, 568 insertions, 0 deletions
diff --git a/src/core/lib/transport/chttp2/hpack_encoder.c b/src/core/lib/transport/chttp2/hpack_encoder.c new file mode 100644 index 0000000000..6b45929b04 --- /dev/null +++ b/src/core/lib/transport/chttp2/hpack_encoder.c @@ -0,0 +1,568 @@ +/* + * + * Copyright 2015-2016, Google Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Google Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +#include "src/core/lib/transport/chttp2/hpack_encoder.h" + +#include <assert.h> +#include <string.h> + +/* This is here for grpc_is_binary_header + * TODO(murgatroid99): Remove this + */ +#include <grpc/grpc.h> + +#include <grpc/support/alloc.h> +#include <grpc/support/log.h> +#include <grpc/support/useful.h> + +#include "src/core/lib/transport/chttp2/bin_encoder.h" +#include "src/core/lib/transport/chttp2/hpack_table.h" +#include "src/core/lib/transport/chttp2/timeout_encoding.h" +#include "src/core/lib/transport/chttp2/varint.h" +#include "src/core/lib/transport/static_metadata.h" + +#define HASH_FRAGMENT_1(x) ((x)&255) +#define HASH_FRAGMENT_2(x) ((x >> 8) & 255) +#define HASH_FRAGMENT_3(x) ((x >> 16) & 255) +#define HASH_FRAGMENT_4(x) ((x >> 24) & 255) + +/* if the probability of this item being seen again is < 1/x then don't add + it to the table */ +#define ONE_ON_ADD_PROBABILITY 128 +/* don't consider adding anything bigger than this to the hpack table */ +#define MAX_DECODER_SPACE_USAGE 512 + +typedef struct { + int is_first_frame; + /* number of bytes in 'output' when we started the frame - used to calculate + frame length */ + size_t output_length_at_start_of_frame; + /* index (in output) of the header for the current frame */ + size_t header_idx; + /* have we seen a regular (non-colon-prefixed) header yet? */ + uint8_t seen_regular_header; + /* output stream id */ + uint32_t stream_id; + gpr_slice_buffer *output; +} framer_state; + +/* fills p (which is expected to be 9 bytes long) with a data frame header */ +static void fill_header(uint8_t *p, uint8_t type, uint32_t id, size_t len, + uint8_t flags) { + GPR_ASSERT(len < 16777316); + *p++ = (uint8_t)(len >> 16); + *p++ = (uint8_t)(len >> 8); + *p++ = (uint8_t)(len); + *p++ = type; + *p++ = flags; + *p++ = (uint8_t)(id >> 24); + *p++ = (uint8_t)(id >> 16); + *p++ = (uint8_t)(id >> 8); + *p++ = (uint8_t)(id); +} + +/* finish a frame - fill in the previously reserved header */ +static void finish_frame(framer_state *st, int is_header_boundary, + int is_last_in_stream) { + uint8_t type = 0xff; + type = st->is_first_frame ? GRPC_CHTTP2_FRAME_HEADER + : GRPC_CHTTP2_FRAME_CONTINUATION; + fill_header( + GPR_SLICE_START_PTR(st->output->slices[st->header_idx]), type, + st->stream_id, st->output->length - st->output_length_at_start_of_frame, + (uint8_t)((is_last_in_stream ? GRPC_CHTTP2_DATA_FLAG_END_STREAM : 0) | + (is_header_boundary ? GRPC_CHTTP2_DATA_FLAG_END_HEADERS : 0))); + st->is_first_frame = 0; +} + +/* begin a new frame: reserve off header space, remember how many bytes we'd + output before beginning */ +static void begin_frame(framer_state *st) { + st->header_idx = + gpr_slice_buffer_add_indexed(st->output, gpr_slice_malloc(9)); + st->output_length_at_start_of_frame = st->output->length; +} + +/* make sure that the current frame is of the type desired, and has sufficient + space to add at least about_to_add bytes -- finishes the current frame if + needed */ +static void ensure_space(framer_state *st, size_t need_bytes) { + if (st->output->length - st->output_length_at_start_of_frame + need_bytes <= + GRPC_CHTTP2_MAX_PAYLOAD_LENGTH) { + return; + } + finish_frame(st, 0, 0); + begin_frame(st); +} + +/* increment a filter count, halve all counts if one element reaches max */ +static void inc_filter(uint8_t idx, uint32_t *sum, uint8_t *elems) { + elems[idx]++; + if (elems[idx] < 255) { + (*sum)++; + } else { + int i; + *sum = 0; + for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_FILTERS; i++) { + elems[i] /= 2; + (*sum) += elems[i]; + } + } +} + +static void add_header_data(framer_state *st, gpr_slice slice) { + size_t len = GPR_SLICE_LENGTH(slice); + size_t remaining; + if (len == 0) return; + remaining = GRPC_CHTTP2_MAX_PAYLOAD_LENGTH + + st->output_length_at_start_of_frame - st->output->length; + if (len <= remaining) { + gpr_slice_buffer_add(st->output, slice); + } else { + gpr_slice_buffer_add(st->output, gpr_slice_split_head(&slice, remaining)); + finish_frame(st, 0, 0); + begin_frame(st); + add_header_data(st, slice); + } +} + +static uint8_t *add_tiny_header_data(framer_state *st, size_t len) { + ensure_space(st, len); + return gpr_slice_buffer_tiny_add(st->output, len); +} + +static void evict_entry(grpc_chttp2_hpack_compressor *c) { + c->tail_remote_index++; + GPR_ASSERT(c->tail_remote_index > 0); + GPR_ASSERT(c->table_size >= + c->table_elem_size[c->tail_remote_index % c->cap_table_elems]); + GPR_ASSERT(c->table_elems > 0); + c->table_size = + (uint16_t)(c->table_size - + c->table_elem_size[c->tail_remote_index % c->cap_table_elems]); + c->table_elems--; +} + +/* add an element to the decoder table */ +static void add_elem(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem) { + uint32_t key_hash = elem->key->hash; + uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, elem->value->hash); + uint32_t new_index = c->tail_remote_index + c->table_elems + 1; + size_t elem_size = 32 + GPR_SLICE_LENGTH(elem->key->slice) + + GPR_SLICE_LENGTH(elem->value->slice); + + GPR_ASSERT(elem_size < 65536); + + if (elem_size > c->max_table_size) { + while (c->table_size > 0) { + evict_entry(c); + } + return; + } + + /* Reserve space for this element in the remote table: if this overflows + the current table, drop elements until it fits, matching the decompressor + algorithm */ + while (c->table_size + elem_size > c->max_table_size) { + evict_entry(c); + } + GPR_ASSERT(c->table_elems < c->max_table_size); + c->table_elem_size[new_index % c->cap_table_elems] = (uint16_t)elem_size; + c->table_size = (uint16_t)(c->table_size + elem_size); + c->table_elems++; + + /* Store this element into {entries,indices}_elem */ + if (c->entries_elems[HASH_FRAGMENT_2(elem_hash)] == elem) { + /* already there: update with new index */ + c->indices_elems[HASH_FRAGMENT_2(elem_hash)] = new_index; + } else if (c->entries_elems[HASH_FRAGMENT_3(elem_hash)] == elem) { + /* already there (cuckoo): update with new index */ + c->indices_elems[HASH_FRAGMENT_3(elem_hash)] = new_index; + } else if (c->entries_elems[HASH_FRAGMENT_2(elem_hash)] == NULL) { + /* not there, but a free element: add */ + c->entries_elems[HASH_FRAGMENT_2(elem_hash)] = GRPC_MDELEM_REF(elem); + c->indices_elems[HASH_FRAGMENT_2(elem_hash)] = new_index; + } else if (c->entries_elems[HASH_FRAGMENT_3(elem_hash)] == NULL) { + /* not there (cuckoo), but a free element: add */ + c->entries_elems[HASH_FRAGMENT_3(elem_hash)] = GRPC_MDELEM_REF(elem); + c->indices_elems[HASH_FRAGMENT_3(elem_hash)] = new_index; + } else if (c->indices_elems[HASH_FRAGMENT_2(elem_hash)] < + c->indices_elems[HASH_FRAGMENT_3(elem_hash)]) { + /* not there: replace oldest */ + GRPC_MDELEM_UNREF(c->entries_elems[HASH_FRAGMENT_2(elem_hash)]); + c->entries_elems[HASH_FRAGMENT_2(elem_hash)] = GRPC_MDELEM_REF(elem); + c->indices_elems[HASH_FRAGMENT_2(elem_hash)] = new_index; + } else { + /* not there: replace oldest */ + GRPC_MDELEM_UNREF(c->entries_elems[HASH_FRAGMENT_3(elem_hash)]); + c->entries_elems[HASH_FRAGMENT_3(elem_hash)] = GRPC_MDELEM_REF(elem); + c->indices_elems[HASH_FRAGMENT_3(elem_hash)] = new_index; + } + + /* do exactly the same for the key (so we can find by that again too) */ + + if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == elem->key) { + c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index; + } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == elem->key) { + c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index; + } else if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == NULL) { + c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key); + c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index; + } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == NULL) { + c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key); + c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index; + } else if (c->indices_keys[HASH_FRAGMENT_2(key_hash)] < + c->indices_keys[HASH_FRAGMENT_3(key_hash)]) { + GRPC_MDSTR_UNREF(c->entries_keys[HASH_FRAGMENT_2(key_hash)]); + c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key); + c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index; + } else { + GRPC_MDSTR_UNREF(c->entries_keys[HASH_FRAGMENT_3(key_hash)]); + c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key); + c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index; + } +} + +static void emit_indexed(grpc_chttp2_hpack_compressor *c, uint32_t elem_index, + framer_state *st) { + uint32_t len = GRPC_CHTTP2_VARINT_LENGTH(elem_index, 1); + GRPC_CHTTP2_WRITE_VARINT(elem_index, 1, 0x80, add_tiny_header_data(st, len), + len); +} + +static gpr_slice get_wire_value(grpc_mdelem *elem, uint8_t *huffman_prefix) { + if (grpc_is_binary_header((const char *)GPR_SLICE_START_PTR(elem->key->slice), + GPR_SLICE_LENGTH(elem->key->slice))) { + *huffman_prefix = 0x80; + return grpc_mdstr_as_base64_encoded_and_huffman_compressed(elem->value); + } + /* TODO(ctiller): opportunistically compress non-binary headers */ + *huffman_prefix = 0x00; + return elem->value->slice; +} + +static void emit_lithdr_incidx(grpc_chttp2_hpack_compressor *c, + uint32_t key_index, grpc_mdelem *elem, + framer_state *st) { + uint32_t len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 2); + uint8_t huffman_prefix; + gpr_slice value_slice = get_wire_value(elem, &huffman_prefix); + size_t len_val = GPR_SLICE_LENGTH(value_slice); + uint32_t len_val_len; + GPR_ASSERT(len_val <= UINT32_MAX); + len_val_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)len_val, 1); + GRPC_CHTTP2_WRITE_VARINT(key_index, 2, 0x40, + add_tiny_header_data(st, len_pfx), len_pfx); + GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix, + add_tiny_header_data(st, len_val_len), len_val_len); + add_header_data(st, gpr_slice_ref(value_slice)); +} + +static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c, + uint32_t key_index, grpc_mdelem *elem, + framer_state *st) { + uint32_t len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 4); + uint8_t huffman_prefix; + gpr_slice value_slice = get_wire_value(elem, &huffman_prefix); + size_t len_val = GPR_SLICE_LENGTH(value_slice); + uint32_t len_val_len; + GPR_ASSERT(len_val <= UINT32_MAX); + len_val_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)len_val, 1); + GRPC_CHTTP2_WRITE_VARINT(key_index, 4, 0x00, + add_tiny_header_data(st, len_pfx), len_pfx); + GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix, + add_tiny_header_data(st, len_val_len), len_val_len); + add_header_data(st, gpr_slice_ref(value_slice)); +} + +static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c, + grpc_mdelem *elem, framer_state *st) { + uint32_t len_key = (uint32_t)GPR_SLICE_LENGTH(elem->key->slice); + uint8_t huffman_prefix; + gpr_slice value_slice = get_wire_value(elem, &huffman_prefix); + uint32_t len_val = (uint32_t)GPR_SLICE_LENGTH(value_slice); + uint32_t len_key_len = GRPC_CHTTP2_VARINT_LENGTH(len_key, 1); + uint32_t len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1); + GPR_ASSERT(len_key <= UINT32_MAX); + GPR_ASSERT(GPR_SLICE_LENGTH(value_slice) <= UINT32_MAX); + *add_tiny_header_data(st, 1) = 0x40; + GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00, + add_tiny_header_data(st, len_key_len), len_key_len); + add_header_data(st, gpr_slice_ref(elem->key->slice)); + GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix, + add_tiny_header_data(st, len_val_len), len_val_len); + add_header_data(st, gpr_slice_ref(value_slice)); +} + +static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c, + grpc_mdelem *elem, framer_state *st) { + uint32_t len_key = (uint32_t)GPR_SLICE_LENGTH(elem->key->slice); + uint8_t huffman_prefix; + gpr_slice value_slice = get_wire_value(elem, &huffman_prefix); + uint32_t len_val = (uint32_t)GPR_SLICE_LENGTH(value_slice); + uint32_t len_key_len = GRPC_CHTTP2_VARINT_LENGTH(len_key, 1); + uint32_t len_val_len = GRPC_CHTTP2_VARINT_LENGTH(len_val, 1); + GPR_ASSERT(len_key <= UINT32_MAX); + GPR_ASSERT(GPR_SLICE_LENGTH(value_slice) <= UINT32_MAX); + *add_tiny_header_data(st, 1) = 0x00; + GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00, + add_tiny_header_data(st, len_key_len), len_key_len); + add_header_data(st, gpr_slice_ref(elem->key->slice)); + GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix, + add_tiny_header_data(st, len_val_len), len_val_len); + add_header_data(st, gpr_slice_ref(value_slice)); +} + +static void emit_advertise_table_size_change(grpc_chttp2_hpack_compressor *c, + framer_state *st) { + uint32_t len = GRPC_CHTTP2_VARINT_LENGTH(c->max_table_size, 3); + GRPC_CHTTP2_WRITE_VARINT(c->max_table_size, 3, 0x20, + add_tiny_header_data(st, len), len); + c->advertise_table_size_change = 0; +} + +static uint32_t dynidx(grpc_chttp2_hpack_compressor *c, uint32_t elem_index) { + return 1 + GRPC_CHTTP2_LAST_STATIC_ENTRY + c->tail_remote_index + + c->table_elems - elem_index; +} + +/* encode an mdelem */ +static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem, + framer_state *st) { + uint32_t key_hash = elem->key->hash; + uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, elem->value->hash); + size_t decoder_space_usage; + uint32_t indices_key; + int should_add_elem; + + GPR_ASSERT(GPR_SLICE_LENGTH(elem->key->slice) > 0); + if (GPR_SLICE_START_PTR(elem->key->slice)[0] != ':') { /* regular header */ + st->seen_regular_header = 1; + } else { + GPR_ASSERT( + st->seen_regular_header == 0 && + "Reserved header (colon-prefixed) happening after regular ones."); + } + + inc_filter(HASH_FRAGMENT_1(elem_hash), &c->filter_elems_sum, c->filter_elems); + + /* is this elem currently in the decoders table? */ + + if (c->entries_elems[HASH_FRAGMENT_2(elem_hash)] == elem && + c->indices_elems[HASH_FRAGMENT_2(elem_hash)] > c->tail_remote_index) { + /* HIT: complete element (first cuckoo hash) */ + emit_indexed(c, dynidx(c, c->indices_elems[HASH_FRAGMENT_2(elem_hash)]), + st); + return; + } + + if (c->entries_elems[HASH_FRAGMENT_3(elem_hash)] == elem && + c->indices_elems[HASH_FRAGMENT_3(elem_hash)] > c->tail_remote_index) { + /* HIT: complete element (second cuckoo hash) */ + emit_indexed(c, dynidx(c, c->indices_elems[HASH_FRAGMENT_3(elem_hash)]), + st); + return; + } + + /* should this elem be in the table? */ + decoder_space_usage = 32 + GPR_SLICE_LENGTH(elem->key->slice) + + GPR_SLICE_LENGTH(elem->value->slice); + should_add_elem = decoder_space_usage < MAX_DECODER_SPACE_USAGE && + c->filter_elems[HASH_FRAGMENT_1(elem_hash)] >= + c->filter_elems_sum / ONE_ON_ADD_PROBABILITY; + + /* no hits for the elem... maybe there's a key? */ + + indices_key = c->indices_keys[HASH_FRAGMENT_2(key_hash)]; + if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == elem->key && + indices_key > c->tail_remote_index) { + /* HIT: key (first cuckoo hash) */ + if (should_add_elem) { + emit_lithdr_incidx(c, dynidx(c, indices_key), elem, st); + add_elem(c, elem); + return; + } else { + emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st); + return; + } + GPR_UNREACHABLE_CODE(return ); + } + + indices_key = c->indices_keys[HASH_FRAGMENT_3(key_hash)]; + if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == elem->key && + indices_key > c->tail_remote_index) { + /* HIT: key (first cuckoo hash) */ + if (should_add_elem) { + emit_lithdr_incidx(c, dynidx(c, indices_key), elem, st); + add_elem(c, elem); + return; + } else { + emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st); + return; + } + GPR_UNREACHABLE_CODE(return ); + } + + /* no elem, key in the table... fall back to literal emission */ + + if (should_add_elem) { + emit_lithdr_incidx_v(c, elem, st); + add_elem(c, elem); + return; + } else { + emit_lithdr_noidx_v(c, elem, st); + return; + } + GPR_UNREACHABLE_CODE(return ); +} + +#define STRLEN_LIT(x) (sizeof(x) - 1) +#define TIMEOUT_KEY "grpc-timeout" + +static void deadline_enc(grpc_chttp2_hpack_compressor *c, gpr_timespec deadline, + framer_state *st) { + char timeout_str[GRPC_CHTTP2_TIMEOUT_ENCODE_MIN_BUFSIZE]; + grpc_mdelem *mdelem; + grpc_chttp2_encode_timeout( + gpr_time_sub(deadline, gpr_now(deadline.clock_type)), timeout_str); + mdelem = grpc_mdelem_from_metadata_strings( + GRPC_MDSTR_GRPC_TIMEOUT, grpc_mdstr_from_string(timeout_str)); + hpack_enc(c, mdelem, st); + GRPC_MDELEM_UNREF(mdelem); +} + +static uint32_t elems_for_bytes(uint32_t bytes) { return (bytes + 31) / 32; } + +void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c) { + memset(c, 0, sizeof(*c)); + c->max_table_size = GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE; + c->cap_table_elems = elems_for_bytes(c->max_table_size); + c->max_table_elems = c->cap_table_elems; + c->max_usable_size = GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE; + c->table_elem_size = + gpr_malloc(sizeof(*c->table_elem_size) * c->cap_table_elems); + memset(c->table_elem_size, 0, + sizeof(*c->table_elem_size) * c->cap_table_elems); +} + +void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c) { + int i; + for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_VALUES; i++) { + if (c->entries_keys[i]) GRPC_MDSTR_UNREF(c->entries_keys[i]); + if (c->entries_elems[i]) GRPC_MDELEM_UNREF(c->entries_elems[i]); + } + gpr_free(c->table_elem_size); +} + +void grpc_chttp2_hpack_compressor_set_max_usable_size( + grpc_chttp2_hpack_compressor *c, uint32_t max_table_size) { + c->max_usable_size = max_table_size; + grpc_chttp2_hpack_compressor_set_max_table_size( + c, GPR_MIN(c->max_table_size, max_table_size)); +} + +static void rebuild_elems(grpc_chttp2_hpack_compressor *c, uint32_t new_cap) { + uint16_t *table_elem_size = gpr_malloc(sizeof(*table_elem_size) * new_cap); + uint32_t i; + + memset(table_elem_size, 0, sizeof(*table_elem_size) * new_cap); + GPR_ASSERT(c->table_elems <= new_cap); + + for (i = 0; i < c->table_elems; i++) { + uint32_t ofs = c->tail_remote_index + i + 1; + table_elem_size[ofs % new_cap] = + c->table_elem_size[ofs % c->cap_table_elems]; + } + + c->cap_table_elems = new_cap; + gpr_free(c->table_elem_size); + c->table_elem_size = table_elem_size; +} + +void grpc_chttp2_hpack_compressor_set_max_table_size( + grpc_chttp2_hpack_compressor *c, uint32_t max_table_size) { + max_table_size = GPR_MIN(max_table_size, c->max_usable_size); + if (max_table_size == c->max_table_size) { + return; + } + while (c->table_size > 0 && c->table_size > max_table_size) { + evict_entry(c); + } + c->max_table_size = max_table_size; + c->max_table_elems = elems_for_bytes(max_table_size); + if (c->max_table_elems > c->cap_table_elems) { + rebuild_elems(c, GPR_MAX(c->max_table_elems, 2 * c->cap_table_elems)); + } else if (c->max_table_elems < c->cap_table_elems / 3) { + uint32_t new_cap = GPR_MAX(c->max_table_elems, 16); + if (new_cap != c->cap_table_elems) { + rebuild_elems(c, new_cap); + } + } + c->advertise_table_size_change = 1; + gpr_log(GPR_DEBUG, "set max table size from encoder to %d", max_table_size); +} + +void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c, + uint32_t stream_id, + grpc_metadata_batch *metadata, int is_eof, + gpr_slice_buffer *outbuf) { + framer_state st; + grpc_linked_mdelem *l; + gpr_timespec deadline; + + GPR_ASSERT(stream_id != 0); + + st.seen_regular_header = 0; + st.stream_id = stream_id; + st.output = outbuf; + st.is_first_frame = 1; + + /* Encode a metadata batch; store the returned values, representing + a metadata element that needs to be unreffed back into the metadata + slot. THIS MAY NOT BE THE SAME ELEMENT (if a decoder table slot got + updated). After this loop, we'll do a batch unref of elements. */ + begin_frame(&st); + if (c->advertise_table_size_change != 0) { + emit_advertise_table_size_change(c, &st); + } + grpc_metadata_batch_assert_ok(metadata); + for (l = metadata->list.head; l; l = l->next) { + hpack_enc(c, l->md, &st); + } + deadline = metadata->deadline; + if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) != 0) { + deadline_enc(c, deadline, &st); + } + + finish_frame(&st, 1, is_eof); +} |