minetestmapper/db-postgresql.cpp

184 lines
4.3 KiB
C++

#include <stdexcept>
#include <iostream>
#include <fstream>
#include <cstdlib>
#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 connect_string = read_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::int4, posY::int4, posZ::int4 FROM blocks WHERE"
" (posX BETWEEN $1::int4 AND $2::int4) AND"
" (posY BETWEEN $3::int4 AND $4::int4) AND"
" (posZ BETWEEN $5::int4 AND $6::int4)"
);
prepareStatement(
"get_blocks",
"SELECT posY::int4, data FROM blocks WHERE"
" posX = $1::int4 AND posZ = $2::int4"
" AND (posY BETWEEN $3::int4 AND $4::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(BlockPos min, BlockPos max)
{
int32_t const x1 = htonl(min.x);
int32_t const x2 = htonl(max.x - 1);
int32_t const y1 = htonl(min.y);
int32_t const y2 = htonl(max.y - 1);
int32_t const z1 = htonl(min.z);
int32_t const z2 = htonl(max.z - 1);
const void *args[] = { &x1, &x2, &y1, &y2, &z1, &z2 };
const int argLen[] = { 4, 4, 4, 4, 4, 4 };
const int argFmt[] = { 1, 1, 1, 1, 1, 1 };
PGresult *results = execPrepared(
"get_block_pos", ARRLEN(args), args,
argLen, argFmt, false
);
int numrows = PQntuples(results);
std::vector<BlockPos> positions;
positions.reserve(numrows);
for (int row = 0; row < numrows; ++row)
positions.emplace_back(pg_to_blockpos(results, row, 0));
PQclear(results);
return positions;
}
void DBPostgreSQL::getBlocksOnXZ(BlockList &blocks, int16_t xPos, int16_t zPos,
int16_t min_y, int16_t max_y)
{
int32_t const x = htonl(xPos);
int32_t const z = htonl(zPos);
int32_t const y1 = htonl(min_y);
int32_t const y2 = htonl(max_y - 1);
const void *args[] = { &x, &z, &y1, &y2 };
const int argLen[] = { 4, 4, 4, 4 };
const int argFmt[] = { 1, 1, 1, 1 };
PGresult *results = execPrepared(
"get_blocks", ARRLEN(args), args,
argLen, argFmt, false
);
int numrows = PQntuples(results);
for (int row = 0; row < numrows; ++row) {
BlockPos position;
position.x = xPos;
position.y = pg_binary_to_int(results, row, 0);
position.z = zPos;
blocks.emplace_back(
position,
ustring(
reinterpret_cast<unsigned char*>(
PQgetvalue(results, row, 1)
),
PQgetlength(results, row, 1)
)
);
}
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
)
{
return checkResults(PQexecPrepared(db, stmtName, paramsNumber,
(const char* const*) params, paramsLengths, paramsFormats,
1 /* binary output */), clear
);
}
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_binary_to_int(res, row, col);
result.y = pg_binary_to_int(res, row, col + 1);
result.z = pg_binary_to_int(res, row, col + 2);
return result;
}