minetestmapper/db-postgresql.cpp

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#include <stdexcept>
#include <iostream>
#include <fstream>
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#include <cstdlib>
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#include <arpa/inet.h>
#include "db-postgresql.h"
#include "util.h"
#include "types.h"
#define ARRLEN(x) (sizeof(x) / sizeof((x)[0]))
DBPostgreSQL::DBPostgreSQL(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 const connect_string = get_setting("pgsql_connection", ifs);
ifs.close();
db = PQconnectdb(connect_string.c_str());
if (PQstatus(db) != CONNECTION_OK) {
throw std::runtime_error(std::string(
"PostgreSQL database error: ") +
PQerrorMessage(db)
);
}
prepareStatement(
"get_block_pos",
"SELECT posX, posY, posZ FROM blocks"
);
prepareStatement(
"get_blocks_z",
"SELECT posX, posY, data FROM blocks WHERE posZ = $1::int4"
);
checkResults(PQexec(db, "START TRANSACTION;"));
checkResults(PQexec(db, "SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;"));
}
DBPostgreSQL::~DBPostgreSQL()
{
try {
checkResults(PQexec(db, "COMMIT;"));
} catch (std::exception& caught) {
std::cerr << "could not finalize: " << caught.what() << std::endl;
}
PQfinish(db);
}
std::vector<BlockPos> DBPostgreSQL::getBlockPos()
{
std::vector<BlockPos> positions;
PGresult *results = execPrepared(
"get_block_pos", 0,
NULL, NULL, NULL, false, false
);
int numrows = PQntuples(results);
for (int row = 0; row < numrows; ++row)
positions.push_back(pg_to_blockpos(results, row, 0));
PQclear(results);
return positions;
}
void DBPostgreSQL::getBlocksOnZ(std::map<int16_t, BlockList> &blocks, int16_t zPos)
{
int32_t const z = htonl(zPos);
const void *args[] = { &z };
const int argLen[] = { sizeof(z) };
const int argFmt[] = { 1 };
PGresult *results = execPrepared(
"get_blocks_z", ARRLEN(args), args,
argLen, argFmt, false
);
int numrows = PQntuples(results);
for (int row = 0; row < numrows; ++row) {
BlockPos position;
position.x = pg_binary_to_int(results, row, 0);
position.y = pg_binary_to_int(results, row, 1);
position.z = zPos;
Block const b(
position,
ustring(
reinterpret_cast<unsigned char*>(
PQgetvalue(results, row, 2)
),
PQgetlength(results, row, 2)
)
);
blocks[position.x].push_back(b);
}
PQclear(results);
}
PGresult *DBPostgreSQL::checkResults(PGresult *res, bool clear)
{
ExecStatusType statusType = PQresultStatus(res);
switch (statusType) {
case PGRES_COMMAND_OK:
case PGRES_TUPLES_OK:
break;
case PGRES_FATAL_ERROR:
throw std::runtime_error(
std::string("PostgreSQL database error: ") +
PQresultErrorMessage(res)
);
default:
throw std::runtime_error(
"Unhandled PostgreSQL result code"
);
}
if (clear)
PQclear(res);
return res;
}
void DBPostgreSQL::prepareStatement(const std::string &name, const std::string &sql)
{
checkResults(PQprepare(db, name.c_str(), sql.c_str(), 0, NULL));
}
PGresult *DBPostgreSQL::execPrepared(
const char *stmtName, const int paramsNumber,
const void **params,
const int *paramsLengths, const int *paramsFormats,
bool clear, bool nobinary
)
{
return checkResults(PQexecPrepared(db, stmtName, paramsNumber,
(const char* const*) params, paramsLengths, paramsFormats,
nobinary ? 1 : 0), clear
);
}
int DBPostgreSQL::pg_to_int(PGresult *res, int row, int col)
{
return atoi(PQgetvalue(res, row, col));
}
int DBPostgreSQL::pg_binary_to_int(PGresult *res, int row, int col)
{
int32_t* raw = reinterpret_cast<int32_t*>(PQgetvalue(res, row, col));
return ntohl(*raw);
}
BlockPos DBPostgreSQL::pg_to_blockpos(PGresult *res, int row, int col)
{
BlockPos result;
result.x = pg_to_int(res, row, col);
result.y = pg_to_int(res, row, col + 1);
result.z = pg_to_int(res, row, col + 2);
return result;
}