minetestmapper/db-redis.cpp

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#include <stdexcept>
#include <sstream>
#include <fstream>
#include "db-redis.h"
#include "types.h"
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#include "util.h"
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#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)
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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;
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tmp = read_setting("redis_address", ifs);
ifs.seekg(0);
hash = read_setting("redis_hash", ifs);
ifs.seekg(0);
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const char *addr = tmp.c_str();
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int port = stoi64(read_setting_default("redis_port", ifs, "6379"));
ctx = tmp.find('/') != std::string::npos ? redisConnectUnix(addr) : redisConnect(addr, port);
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if(!ctx) {
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throw std::runtime_error("Cannot allocate redis context");
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} else if(ctx->err) {
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std::string err = std::string("Connection error: ") + ctx->errstr;
redisFree(ctx);
throw std::runtime_error(err);
}
loadPosCache();
}
DBRedis::~DBRedis()
{
redisFree(ctx);
}
std::vector<BlockPos> DBRedis::getBlockPos()
{
return posCache;
}
std::string 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";
}
}
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void DBRedis::loadPosCache()
{
redisReply *reply;
reply = (redisReply*) redisCommand(ctx, "HKEYS %s", hash.c_str());
if(!reply)
throw std::runtime_error("Redis command HKEYS failed");
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if(reply->type != REDIS_REPLY_ARRAY)
REPLY_TYPE_ERR(reply, "HKEYS reply");
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for(size_t i = 0; i < reply->elements; i++) {
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if(reply->element[i]->type != REDIS_REPLY_STRING)
REPLY_TYPE_ERR(reply->element[i], "HKEYS subreply");
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posCache.push_back(decodeBlockPos(stoi64(reply->element[i]->str)));
}
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freeReplyObject(reply);
}
void DBRedis::HMGET(const std::vector<BlockPos> &positions, std::vector<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();
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) {
freeReplyObject(reply);
REPLY_TYPE_ERR(reply, "HKEYS subreply");
}
if (reply->elements != batch_size) {
freeReplyObject(reply);
throw std::runtime_error("HMGET wrong number of elements");
}
for (std::size_t i = 0; i < batch_size; ++i) {
redisReply *subreply = reply->element[i];
if(!subreply)
throw std::runtime_error("Redis command HMGET failed");
if (subreply->type != REDIS_REPLY_STRING) {
freeReplyObject(reply);
REPLY_TYPE_ERR(reply, "HKEYS subreply");
}
if (subreply->len == 0) {
freeReplyObject(reply);
throw std::runtime_error("HMGET empty string");
}
result->push_back(ustring((const unsigned char *) subreply->str, subreply->len));
}
freeReplyObject(reply);
remaining -= batch_size;
}
}
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void DBRedis::getBlocksOnZ(std::map<int16_t, BlockList> &blocks, int16_t zPos)
{
std::vector<BlockPos> z_positions;
for (std::vector<BlockPos>::const_iterator it = posCache.begin(); it != posCache.end(); ++it) {
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if (it->z != zPos) {
continue;
}
z_positions.push_back(*it);
}
std::vector<ustring> z_blocks;
HMGET(z_positions, &z_blocks);
std::vector<ustring>::const_iterator z_block = z_blocks.begin();
for (std::vector<BlockPos>::const_iterator pos = z_positions.begin();
pos != z_positions.end();
++pos, ++z_block) {
blocks[pos->x].push_back(Block(*pos, *z_block));
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}
}