PostgreSQL database support

CMakeLists.txt

@@ -78,6 +78,39 @@ if(NOT SQLITE3_LIBRARY OR NOT SQLITE3_INCLUDE_DIR)
 	message(FATAL_ERROR "sqlite3 not found!")
 endif(NOT SQLITE3_LIBRARY OR NOT SQLITE3_INCLUDE_DIR)
 
+# Libraries: postgresql
+
+option(ENABLE_POSTGRESQL "Enable PostgreSQL backend" TRUE)
+set(USE_POSTGRESQL 0)
+
+if(ENABLE_POSTGRESQL)
+	find_program(POSTGRESQL_CONFIG_EXECUTABLE pg_config DOC "pg_config")
+	find_library(POSTGRESQL_LIBRARY pq)
+	if(POSTGRESQL_CONFIG_EXECUTABLE)
+		execute_process(COMMAND ${POSTGRESQL_CONFIG_EXECUTABLE} --includedir-server
+			OUTPUT_VARIABLE POSTGRESQL_SERVER_INCLUDE_DIRS
+			OUTPUT_STRIP_TRAILING_WHITESPACE)
+		execute_process(COMMAND ${POSTGRESQL_CONFIG_EXECUTABLE}
+			OUTPUT_VARIABLE POSTGRESQL_CLIENT_INCLUDE_DIRS
+			OUTPUT_STRIP_TRAILING_WHITESPACE)
+		# This variable is case sensitive for the cmake PostgreSQL module
+		set(PostgreSQL_ADDITIONAL_SEARCH_PATHS ${POSTGRESQL_SERVER_INCLUDE_DIRS} ${POSTGRESQL_CLIENT_INCLUDE_DIRS})
+	endif()
+
+	find_package("PostgreSQL")
+
+	if(POSTGRESQL_FOUND)
+		set(USE_POSTGRESQL 1)
+		message(STATUS "PostgreSQL backend enabled")
+		# This variable is case sensitive, don't try to change it to POSTGRESQL_INCLUDE_DIR
+		message(STATUS "PostgreSQL includes: ${PostgreSQL_INCLUDE_DIR}")
+		include_directories(${PostgreSQL_INCLUDE_DIR})
+		set(POSTGRESQL_LIBRARY ${PostgreSQL_LIBRARIES})
+	else()
+		message(STATUS "PostgreSQL not found!")
+	endif()
+endif(ENABLE_POSTGRESQL)
+
 # Libraries: leveldb
 
 set(USE_LEVELDB 0)
@@ -148,6 +181,10 @@ set(mapper_SRCS
 	db-sqlite3.cpp
 )
 
+if(USE_POSTGRESQL)
+	set(mapper_SRCS ${mapper_SRCS} db-postgresql.cpp)
+endif(USE_POSTGRESQL)
+
 if(USE_LEVELDB)
 	set(mapper_SRCS ${mapper_SRCS} db-leveldb.cpp)
 endif(USE_LEVELDB)
@@ -163,6 +200,7 @@ add_executable(minetestmapper
 target_link_libraries(
 	minetestmapper
 	${SQLITE3_LIBRARY}
+	${POSTGRESQL_LIBRARY}
 	${LEVELDB_LIBRARY}
 	${REDIS_LIBRARY}
 	${LIBGD_LIBRARY}

TileGenerator.cpp

@@ -13,6 +13,9 @@
 #include "ZlibDecompressor.h"
 #include "util.h"
 #include "db-sqlite3.h"
+#if USE_POSTGRESQL
+#include "db-postgresql.h"
+#endif
 #if USE_LEVELDB
 #include "db-leveldb.h"
 #endif
@@ -283,6 +286,10 @@ void TileGenerator::openDb(const std::string &input)
 
 	if(backend == "sqlite3")
 		m_db = new DBSQLite3(input);
+#if USE_POSTGRESQL
+	else if(backend == "postgresql")
+		m_db = new DBPostgreSQL(input);
+#endif
 #if USE_LEVELDB
 	else if(backend == "leveldb")
 		m_db = new DBLevelDB(input);

cmake_config.h.in

@@ -3,6 +3,7 @@
 #ifndef CMAKE_CONFIG_H
 #define CMAKE_CONFIG_H
 
+#define USE_POSTGRESQL @USE_POSTGRESQL@
 #define USE_LEVELDB @USE_LEVELDB@
 #define USE_REDIS @USE_REDIS@
 

config.h

@@ -9,6 +9,7 @@
 #ifdef USE_CMAKE_CONFIG_H
 #include "cmake_config.h"
 #else
+#define USE_POSTGRESQL 0
 #define USE_LEVELDB 0
 #define USE_REDIS 0
 

db-postgresql.cpp

@@ -0,0 +1,167 @@
+#include <stdexcept>
+#include <iostream>
+#include <fstream>
+#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;
+}

db-postgresql.h

@@ -0,0 +1,29 @@
+#ifndef _DB_POSTGRESQL_H
+#define _DB_POSTGRESQL_H
+
+#include "db.h"
+#include <libpq-fe.h>
+
+class DBPostgreSQL : public DB {
+public:
+	DBPostgreSQL(const std::string &mapdir);
+	virtual std::vector<BlockPos> getBlockPos();
+	virtual void getBlocksOnZ(std::map<int16_t, BlockList> &blocks, int16_t zPos);
+	virtual ~DBPostgreSQL();
+protected:
+	PGresult *checkResults(PGresult *res, bool clear = true);
+	void prepareStatement(const std::string &name, const std::string &sql);
+	PGresult *execPrepared(
+		const char *stmtName, const int paramsNumber,
+		const void **params,
+		const int *paramsLengths = NULL, const int *paramsFormats = NULL,
+		bool clear = true, bool nobinary = true
+	);
+	int pg_to_int(PGresult *res, int row, int col);
+	int pg_binary_to_int(PGresult *res, int row, int col);
+	BlockPos pg_to_blockpos(PGresult *res, int row, int col);
+private:
+	PGconn *db;
+};
+
+#endif // _DB_POSTGRESQL_H