dragonfly/server/memcache_parser.cc

148 lines
4.0 KiB
C++

// Copyright 2021, Roman Gershman. All rights reserved.
// See LICENSE for licensing terms.
//
#include "server/memcache_parser.h"
#include <absl/strings/ascii.h>
#include <absl/strings/numbers.h>
namespace dfly {
using namespace std;
namespace {
pair<string_view, MemcacheParser::CmdType> cmd_map[] = {
{"set", MemcacheParser::SET}, {"add", MemcacheParser::ADD},
{"replace", MemcacheParser::REPLACE}, {"append", MemcacheParser::APPEND},
{"prepend", MemcacheParser::PREPEND}, {"cas", MemcacheParser::CAS},
{"get", MemcacheParser::GET}, {"gets", MemcacheParser::GETS},
{"gat", MemcacheParser::GAT}, {"gats", MemcacheParser::GATS},
};
MemcacheParser::CmdType From(string_view token) {
for (const auto& k_v : cmd_map) {
if (token == k_v.first)
return k_v.second;
}
return MemcacheParser::INVALID;
}
MemcacheParser::Result ParseStore(const std::string_view* tokens, unsigned num_tokens,
MemcacheParser::Command* res) {
unsigned opt_pos = 3;
if (res->type == MemcacheParser::CAS) {
if (num_tokens <= opt_pos)
return MemcacheParser::PARSE_ERROR;
++opt_pos;
}
uint32_t flags;
if (!absl::SimpleAtoi(tokens[0], &flags) || !absl::SimpleAtoi(tokens[1], &res->expire_ts) ||
!absl::SimpleAtoi(tokens[2], &res->bytes_len))
return MemcacheParser::BAD_INT;
if (flags > 0xFFFF)
return MemcacheParser::BAD_INT;
if (res->type == MemcacheParser::CAS && !absl::SimpleAtoi(tokens[3], &res->cas_unique)) {
return MemcacheParser::BAD_INT;
}
res->flags = flags;
if (num_tokens == opt_pos + 1) {
if (tokens[opt_pos] == "noreply") {
res->no_reply = true;
} else {
return MemcacheParser::PARSE_ERROR;
}
} else if (num_tokens > opt_pos + 1) {
return MemcacheParser::PARSE_ERROR;
}
return MemcacheParser::OK;
}
MemcacheParser::Result ParseRetrieve(const std::string_view* tokens, unsigned num_tokens,
MemcacheParser::Command* res) {
unsigned key_pos = 0;
if (res->type == MemcacheParser::GAT || res->type == MemcacheParser::GATS) {
if (!absl::SimpleAtoi(tokens[0], &res->expire_ts)) {
return MemcacheParser::BAD_INT;
}
++key_pos;
}
res->key = tokens[key_pos++];
while (key_pos < num_tokens) {
res->keys_ext.push_back(tokens[key_pos++]);
}
return MemcacheParser::OK;
}
} // namespace
auto MemcacheParser::Parse(string_view str, uint32_t* consumed, Command* res) -> Result {
auto pos = str.find('\n');
*consumed = 0;
if (pos == string_view::npos) {
// TODO: it's over simplified since we may process gets command that is not limited to
// 300 characters.
return str.size() > 300 ? PARSE_ERROR : INPUT_PENDING;
}
if (pos == 0 || str[pos - 1] != '\r') {
return PARSE_ERROR;
}
*consumed = pos + 1;
// cas <key> <flags> <exptime> <bytes> <cas unique> [noreply]\r\n
// get <key>*\r\n
string_view tokens[8];
unsigned num_tokens = 0;
uint32_t cur = 0;
while (cur < pos && str[cur] == ' ')
++cur;
uint32_t s = cur;
for (; cur < pos; ++cur) {
if (str[cur] == ' ' || str[cur] == '\r') {
if (cur != s) {
tokens[num_tokens++] = str.substr(s, cur - s);
if (num_tokens == ABSL_ARRAYSIZE(tokens)) {
++cur;
s = cur;
break;
}
}
s = cur + 1;
}
}
if (num_tokens == 0)
return PARSE_ERROR;
while (cur < pos - 1) {
if (str[cur] != ' ')
return PARSE_ERROR;
++cur;
}
res->type = From(tokens[0]);
if (res->type == INVALID) {
return UNKNOWN_CMD;
}
if (res->type <= CAS) { // Store command
if (num_tokens < 5 || tokens[1].size() > 250) {
return MemcacheParser::PARSE_ERROR;
}
// memcpy(single_key_, tokens[0].data(), tokens[0].size()); // we copy the key
res->key = string_view{tokens[1].data(), tokens[1].size()};
return ParseStore(tokens + 2, num_tokens - 2, res);
}
return ParseRetrieve(tokens + 1, num_tokens - 1, res);
};
} // namespace dfly