uint32_t HPACKDecoder::emit(const HPACKHeader& header, headers_t* emitted) {
if (streamingCb_) {
streamingCb_->onHeader(header.name, header.value);
} else if (emitted) {
emitted->push_back(header);
}
return header.bytes();
}
bool HeaderTable::add(const HPACKHeader& header) {
// handle size overflow
if (bytes_ + header.bytes() > capacity_) {
evict(header.bytes());
}
// this means the header entry is larger than our table
if (bytes_ + header.bytes() > capacity_) {
return false;
}
if (size_ > 0) {
head_ = next(head_);
}
table_[head_] = header;
// index name
names_[header.name].push_back(head_);
bytes_ += header.bytes();
++size_;
return true;
}
void HPACKEncoder::encodeEvictedReferences(const HPACKHeader& header) {
uint32_t index = table_.size();
uint32_t bytes = table_.bytes();
// the header will be added to the header table
while (index > 0 && (bytes + header.bytes() > table_.capacity())) {
// double encode only if the element is in the reference set
if (table_.isSkippedReference(index)) {
// 1. this will remove the entry from the refset
encodeAsIndex(dynamicToGlobalIndex(index));
// 2. this will add the same entry to the refset and emit it
encodeAsIndex(dynamicToGlobalIndex(index));
}
bytes -= table_[index].bytes();
index--;
}
}
void HPACKEncoder::encodeAsLiteral(const HPACKHeader& header) {
bool indexing = header.isIndexable();
uint8_t prefix = indexing ?
HPACK::HeaderEncoding::LITERAL_INCR_INDEXING :
HPACK::HeaderEncoding::LITERAL_NO_INDEXING;
// name
uint32_t index = nameIndex(header.name);
if (index) {
buffer_.encodeInteger(index, prefix, 6);
} else {
buffer_.encodeInteger(0, prefix, 6);
buffer_.encodeLiteral(header.name);
}
// value
buffer_.encodeLiteral(header.value);
// indexed ones need to get added to the header table
if (indexing) {
if (table_.add(header)) {
table_.addReference(1);
}
}
}
bool HPACKEncoder::willBeAdded(const HPACKHeader& header) {
auto index = getIndex(header);
return isStatic(index) || (index == 0 && header.isIndexable());
}
uint32_t HPACKDecoder::emit(const HPACKHeader& header,
headers_t& emitted) {
emitted.push_back(header);
return header.bytes();
}