bool SPDYUtil::hasGzipAndDeflate(const std::string& value, bool& hasGzip,
bool& hasDeflate) {
static folly::ThreadLocal<std::vector<RFC2616::TokenQPair>> output;
output->clear();
hasGzip = false;
hasDeflate = false;
RFC2616::parseQvalues(value, *output);
for (const auto& encodingQ: *output) {
std::string lower(encodingQ.first.str());
std::transform(lower.begin(), lower.end(), lower.begin(), ::tolower);
// RFC says 3 sig figs
if (lower == "gzip" && encodingQ.second >= 0.001) {
hasGzip = true;
} else if (lower == "deflate" && encodingQ.second >= 0.001) {
hasDeflate = true;
}
}
return hasGzip && hasDeflate;
}
bool parseQvalues(folly::StringPiece value, std::vector<TokenQPair> &output) {
bool result = true;
static folly::ThreadLocal<std::vector<folly::StringPiece>> tokens;
tokens->clear();
folly::split(",", value, *tokens, true /*ignore empty*/);
for (auto& token: *tokens) {
auto pos = token.find(';');
double qvalue = 1.0;
if (pos != std::string::npos) {
auto qpos = token.find("q=", pos);
if (qpos != std::string::npos) {
folly::StringPiece qvalueStr(token.data() + qpos + 2,
token.size() - (qpos + 2));
try {
qvalue = folly::to<double>(&qvalueStr);
} catch (const std::range_error&) {
// q=<some garbage>
result = false;
}
// we could validate that the remainder of qvalueStr was all whitespace,
// for now we just discard it
} else {
// ; but no q=
result = false;
}
token.reset(token.start(), pos);
}
// strip leading whitespace
while (token.size() > 0 && isspace(token[0])) {
token.reset(token.start() + 1, token.size() - 1);
}
if (token.size() == 0) {
// empty token
result = false;
} else {
output.emplace_back(token, qvalue);
}
}
return result && output.size() > 0;
}