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Get rid of regex in http parser

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It's slow.  Replacing it doubles throughput to 110K req/s.
This commit is contained in:
Avi Kivity
2014-08-20 16:37:11 +03:00
parent 26527252c5
commit 10695644d7
1 changed files with 111 additions and 24 deletions
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135
httpd.cc
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@@ -6,20 +6,33 @@
#include "sstring.hh"
#include <iostream>
#include <algorithm>
#include <regex>
#include <unordered_map>
#include <queue>
#include <bitset>
#include <limits>
#include <cctype>
sstring to_sstring(const std::csub_match& sm) {
return sstring(sm.first, sm.second);
}
class char_filter {
using uchar = unsigned char;
public:
template <typename Pred>
explicit char_filter(Pred pred) {
for (unsigned i = 0; i <= std::numeric_limits<uchar>::max(); ++i) {
_filter.set(i, pred(i));
}
}
bool operator()(char v) const { return _filter.test(uchar(v)); }
private:
std::bitset<1 << std::numeric_limits<uchar>::digits> _filter;
};
static std::string tchar = "[-!#$%&'\\*\\+.^_`|~0-9A-Za-z]";
static std::string token = tchar + "+";
static constexpr auto re_opt = std::regex::ECMAScript | std::regex::optimize;
static std::regex start_line_re { "([A-Z]+) (\\S+) HTTP/([0-9]\\.[0-9])\\r\\n", re_opt };
static std::regex header_re { "(" + token + ")\\s*:\\s*(.*\\S)\\s*\\r\\n", re_opt };
static std::regex header_cont_re { "\\s+(.*\\S)\\s*\\r\\n", re_opt };
char_filter tchar([](char c) {
return std::isalnum(c) || std::string("-!#$%&'\\*\\+.^_`|~").find_first_of(c) != std::string::npos;
});
char_filter op_char([](char c) { return std::isupper(c); });
char_filter sp_char([](char c) { return std::isspace(c); });
char_filter nsp_char([](char c) { return !std::isspace(c); });
char_filter digit_char([](char c) { return std::isdigit(c); });
class http_server {
std::vector<pollable_fd> _listeners;
@@ -71,14 +84,62 @@ public:
maybe_done();
return;
}
std::cmatch match;
if (!std::regex_match(start_line.begin(), start_line.end(), match, start_line_re)) {
_req = std::make_unique<request>();
size_t pos = 0;
size_t end = start_line.size();
while (pos < end && op_char(start_line[pos])) {
++pos;
}
if (pos == 0) {
return bad(std::move(_req));
}
_req->_method = sstring(start_line.begin(), pos);
if (pos == end || start_line[pos++] != ' ') {
return bad(std::move(_req));
}
auto url = pos;
while (pos < end && nsp_char(start_line[pos])) {
++pos;
}
_req->_url = sstring(start_line.begin() + url, pos - url);
if (pos == end || start_line[pos++] != ' ') {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != 'H') {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != 'T') {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != 'T') {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != 'P') {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != '/') {
return bad(std::move(_req));
}
auto ver = pos;
if (pos == end || !digit_char(start_line[pos++])) {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != '.') {
return bad(std::move(_req));
}
if (pos == end || !digit_char(start_line[pos++])) {
return bad(std::move(_req));
}
_req->_version = sstring(start_line.begin() + ver, pos - ver);
if (pos == end || start_line[pos++] != '\r') {
return bad(std::move(_req));
}
if (pos == end || start_line[pos++] != '\n') {
return bad(std::move(_req));
}
if (pos != end) {
return bad(std::move(_req));
}
_req = std::make_unique<request>();
_req->_method = to_sstring(match[1]);
_req->_url = to_sstring(match[2]);
_req->_version = to_sstring(match[3]);
if (_req->_method != "GET") {
return bad(std::move(_req));
}
@@ -93,17 +154,43 @@ public:
read();
return;
}
std::cmatch match;
if (std::regex_match(header.begin(), header.end(), match, header_re)) {
sstring name = to_sstring(match[1]);
sstring value = to_sstring(match[2]);
size_t pos = 0;
size_t end = header.size();
if (end < 2 || header[end-2] != '\r' || header[end-1] != '\n') {
return bad(std::move(_req));
}
while (tchar(header[pos])) {
++pos;
}
if (pos) {
sstring name = sstring(header.begin(), pos);
while (pos != end && sp_char(header[pos])) {
++pos;
}
if (pos == end || header[pos++] != ':') {
return bad(std::move(_req));
}
while (pos != end && sp_char(header[pos])) {
++pos;
}
while (pos != end && sp_char(header[end-1])) {
--end;
}
sstring value = sstring(header.begin() + pos, end - pos);
_req->_headers[name] = std::move(value);
_last_header_name = std::move(name);
} else if (std::regex_match(header.begin(), header.end(), match, header_cont_re)) {
_req->_headers[_last_header_name] += " ";
_req->_headers[_last_header_name] += to_sstring(match[1]);
} else {
return bad(std::move(_req));
while (sp_char(header[pos])) {
++pos;
}
while (pos != end && sp_char(header[end-1])) {
--end;
}
if (!pos || end == pos) {
return bad(std::move(_req));
}
_req->_headers[_last_header_name] += " ";
_req->_headers[_last_header_name] += sstring(header.begin() + pos, end - pos);
}
_read_buf.read_until(limit, '\n').then([this] (tmp_buf header) {
parse_header(std::move(header));