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#include <stdexcept>
#include <sstream>
#include <fstream>
#include "db-redis.h"
#include "types.h"
#include "util.h"
#define DB_REDIS_HMGET_NUMFIELDS 30
#define REPLY_TYPE_ERR(reply, desc) do { \
throw std::runtime_error(std::string("Unexpected type for " desc ": ") \
+ replyTypeStr((reply)->type)); \
} while(0)
static inline int64_t stoi64(const std::string &s)
{
std::stringstream tmp(s);
int64_t t;
tmp >> t;
return t;
}
static inline std::string i64tos(int64_t i)
{
std::ostringstream os;
os << i;
return os.str();
}
DBRedis::DBRedis(const std::string &mapdir)
{
std::ifstream ifs((mapdir + "/world.mt").c_str());
if(!ifs.good())
throw std::runtime_error("Failed to read world.mt");
std::string tmp;
tmp = read_setting("redis_address", ifs);
ifs.seekg(0);
hash = read_setting("redis_hash", ifs);
ifs.seekg(0);
const char *addr = tmp.c_str();
int port = stoi64(read_setting_default("redis_port", ifs, "6379"));
ctx = tmp.find('/') != std::string::npos ? redisConnectUnix(addr) : redisConnect(addr, port);
if(!ctx) {
throw std::runtime_error("Cannot allocate redis context");
} else if(ctx->err) {
std::string err = std::string("Connection error: ") + ctx->errstr;
redisFree(ctx);
throw std::runtime_error(err);
}
/* Redis is just a key-value store, so the only optimization we can do
* is to cache the block positions that exist in the db.
*/
loadPosCache();
}
DBRedis::~DBRedis()
{
redisFree(ctx);
}
std::vector<BlockPos> DBRedis::getBlockPos(BlockPos min, BlockPos max)
{
std::vector<BlockPos> res;
for (const auto &it : posCache) {
if (it.first < min.z || it.first >= max.z)
continue;
for (auto pos2 : it.second) {
if (pos2.first < min.x || pos2.first >= max.x)
continue;
if (pos2.second < min.y || pos2.second >= max.y)
continue;
res.emplace_back(pos2.first, pos2.second, it.first);
}
}
return res;
}
const char *DBRedis::replyTypeStr(int type) {
switch(type) {
case REDIS_REPLY_STATUS:
return "REDIS_REPLY_STATUS";
case REDIS_REPLY_ERROR:
return "REDIS_REPLY_ERROR";
case REDIS_REPLY_INTEGER:
return "REDIS_REPLY_INTEGER";
case REDIS_REPLY_NIL:
return "REDIS_REPLY_NIL";
case REDIS_REPLY_STRING:
return "REDIS_REPLY_STRING";
case REDIS_REPLY_ARRAY:
return "REDIS_REPLY_ARRAY";
default:
return "unknown";
}
}
void DBRedis::loadPosCache()
{
redisReply *reply;
reply = (redisReply*) redisCommand(ctx, "HKEYS %s", hash.c_str());
if(!reply)
throw std::runtime_error("Redis command HKEYS failed");
if(reply->type != REDIS_REPLY_ARRAY)
REPLY_TYPE_ERR(reply, "HKEYS reply");
for(size_t i = 0; i < reply->elements; i++) {
if(reply->element[i]->type != REDIS_REPLY_STRING)
REPLY_TYPE_ERR(reply->element[i], "HKEYS subreply");
BlockPos pos = decodeBlockPos(stoi64(reply->element[i]->str));
posCache[pos.z].emplace_back(pos.x, pos.y);
}
freeReplyObject(reply);
}
void DBRedis::HMGET(const std::vector<BlockPos> &positions,
std::function<void(std::size_t, ustring)> result)
{
const char *argv[DB_REDIS_HMGET_NUMFIELDS + 2];
argv[0] = "HMGET";
argv[1] = hash.c_str();
std::vector<BlockPos>::const_iterator position = positions.begin();
std::size_t remaining = positions.size();
std::size_t abs_i = 0;
while (remaining > 0) {
const std::size_t batch_size =
(remaining > DB_REDIS_HMGET_NUMFIELDS) ? DB_REDIS_HMGET_NUMFIELDS : remaining;
redisReply *reply;
{
// storage to preserve validity of .c_str()
std::string keys[batch_size];
for (std::size_t i = 0; i < batch_size; ++i) {
keys[i] = i64tos(encodeBlockPos(*position++));
argv[i+2] = keys[i].c_str();
}
reply = (redisReply*) redisCommandArgv(ctx, batch_size + 2, argv, NULL);
}
if(!reply)
throw std::runtime_error("Redis command HMGET failed");
if (reply->type != REDIS_REPLY_ARRAY)
REPLY_TYPE_ERR(reply, "HMGET reply");
if (reply->elements != batch_size) {
freeReplyObject(reply);
throw std::runtime_error("HMGET wrong number of elements");
}
for (std::size_t i = 0; i < reply->elements; ++i) {
redisReply *subreply = reply->element[i];
if (subreply->type == REDIS_REPLY_NIL)
continue;
else if (subreply->type != REDIS_REPLY_STRING)
REPLY_TYPE_ERR(subreply, "HMGET subreply");
if (subreply->len == 0)
throw std::runtime_error("HMGET empty string");
result(abs_i + i, ustring((const unsigned char *) subreply->str, subreply->len));
}
freeReplyObject(reply);
abs_i += reply->elements;
remaining -= batch_size;
}
}
void DBRedis::getBlocksOnXZ(BlockList &blocks, int16_t x, int16_t z,
int16_t min_y, int16_t max_y)
{
auto it = posCache.find(z);
if (it == posCache.cend())
return;
std::vector<BlockPos> positions;
for (auto pos2 : it->second) {
if (pos2.first == x && pos2.second >= min_y && pos2.second < max_y)
positions.emplace_back(x, pos2.second, z);
}
getBlocksByPos(blocks, positions);
}
void DBRedis::getBlocksByPos(BlockList &blocks,
const std::vector<BlockPos> &positions)
{
auto result = [&] (std::size_t i, ustring data) {
blocks.emplace_back(positions[i], std::move(data));
};
HMGET(positions, result);
}
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