--- sql/pgsql/parser3pgsql.C	2007/01/29 10:22:45	1.27
+++ sql/pgsql/parser3pgsql.C	2019/10/25 12:27:44	1.45
@@ -1,13 +1,12 @@
 /** @file
 	Parser PgSQL driver.
 
-	Copyright(c) 2001, 2003 ArtLebedev Group (http://www.artlebedev.com)
+	Copyright (c) 2001-2015 Art. Lebedev Studio (http://www.artlebedev.com)
 
 	Author: Alexandr Petrosian <paf@design.ru> (http://paf.design.ru)
 
-	2001.07.30 using PgSQL 7.1.2
+	2007.10.25 using PgSQL 8.1.5
 */
-static const char *RCSId="$Id: parser3pgsql.C,v 1.27 2007/01/29 10:22:45 misha Exp $"; 
 
 #include "config_includes.h"
 
@@ -16,17 +15,32 @@ static const char *RCSId="$Id: parser3pg
 #include <libpq-fe.h>
 #include <libpq/libpq-fs.h>
 
-// OIDOID from catalog/pg_type.h
+volatile const char * IDENT_PARSER3PGSQL_C="$Id: parser3pgsql.C,v 1.45 2019/10/25 12:27:44 moko Exp $" IDENT_PA_SQL_DRIVER_H;
+
+// from catalog/pg_type.h
+#define BOOLOID			16
+#define INT8OID			20
+#define INT2OID			21
+#define INT4OID			23
 #define OIDOID			26
+#define FLOAT4OID		700
+#define FLOAT8OID		701
+#define DATEOID			1082
+#define TIMEOID			1083
+#define TIMESTAMPOID	1114
+#define TIMESTAMPTZOID	1184
+#define TIMETZOID		1266
+#define NUMERICOID		1700
+
 // LO_BUFSIZE from interfaces\libpq\fe-lobj.c = 8192 (0x2000)
 // actually writing chunks of that size failed, reduced it twice
 #define LO_BUFSIZE		  0x1000
-// from postgres_ext.h
-//#define InvalidOid		((Oid) 0)
 
 
 #include "ltdl.h"
 
+#define MAX_COLS 500
+
 #define MAX_STRING 0x400
 #define MAX_NUMBER 20
 
@@ -36,49 +50,57 @@ static const char *RCSId="$Id: parser3pg
 #endif
 
 #ifndef max
-inline int max(int a,int b) { return a>b?a:b; }
+inline int max(int a,int b){ return a>b?a:b; }
 inline int min(int a,int b){ return a<b?a:b; }
 #endif
 
-static char *lsplit(char *string, char delim) {
-    if(string) {
-		char *v=strchr(string, delim);
-		if(v) {
+static char *lsplit(char *string, char delim){
+	if(string){
+		if(char *v=strchr(string, delim)){
 			*v=0;
 			return v+1;
 		}
-    }
-    return 0;
+	}
+	return 0;
 }
 
-static char *lsplit(char **string_ref, char delim) {
-    char *result=*string_ref;
+static char *lsplit(char **string_ref, char delim){
+	char *result=*string_ref;
 	char *next=lsplit(*string_ref, delim);
-    *string_ref=next;
-    return result;
+	*string_ref=next;
+	return result;
 }
 
-static char* rsplit(char* string, char delim) {
-    if(string) {
-		char* v=strrchr(string, delim); 
-		if(v) {
+static char* rsplit(char* string, char delim){
+	if(string){
+		if(char* v=strrchr(string, delim)){
 			*v=0;
 			return v+1;
 		}
-    }
-    return NULL;	
+	}
+	return NULL;	
 }
 
-static void toupper_str(char *out, const char *in, size_t size) {
+static void toupper_str(char *out, const char *in, size_t size){
 	while(size--)
 		*out++=(char)toupper(*in++);
 }
 
+inline static const char* strdup(SQL_Driver_services& services, char* str, size_t length) {
+	char *strm=(char*)services.malloc_atomic(length+1);
+	memcpy(strm, str, length);
+	strm[length]=0;
+	return (const char*)strm;
+}
+
 struct Connection {
 	SQL_Driver_services* services;
 
 	PGconn *conn;
-	const char* cstrClientCharset;
+	const char* client_charset;
+	bool autocommit;
+	bool with_default_transactions;
+	bool standard_conforming_strings;
 };
 
 /**
@@ -91,9 +113,10 @@ public:
 	}
 
 	/// get api version
-	int api_version() { return SQL_DRIVER_API_VERSION; }
+	int api_version(){ return SQL_DRIVER_API_VERSION; }
+
 	/// initialize driver by loading sql dynamic link library
-	const char *initialize(char *dlopen_file_spec) {
+	const char *initialize(char *dlopen_file_spec){
 		return dlopen_file_spec?
 			dlink(dlopen_file_spec):"client library column is empty";
 	}
@@ -107,58 +130,75 @@ public:
 
 	/**	connect
 		@param url
-			format: @b user:pass@host[:port]|[local]/database
+			format: @b user:pass@host[:port]|[local]/database?
+			ClientCharset=charset&	// transcode by parser
+			charset=value&			// transcode by server with 'SET CLIENT_ENCODING=value'
+			datestyle=value&		// 'SET DATESTYLE=value' available values are: ISO|SQL|Postgres|European|US|German [default=ISO]
+			autocommit=0&			// 1 -- each statement is commited automatically, only when with_default_transaction enabled
+			standard_conforming_strings=1&	// 0 -- escape \ char that could be needed for old servers
+			with_default_transaction=0	// 1 -- wrap connection into BEGIN TRAN/COMMIT/ROLLBACK
 	*/
 	void connect(
-		char *url, 
-		SQL_Driver_services& services, 
-		void **connection_ref ///< output: Connection*
-		) {
-		char *user=url;
-		char *host=rsplit(user, '@');
-		char *db=lsplit(host, '/');
-		char *pwd=lsplit(user, ':');
-		char *port=lsplit(host, ':');
+				char* url, 
+				SQL_Driver_services& services, 
+				void** connection_ref ///< output: Connection*
+	){
+		char* user=url;
+		char* host=rsplit(user, '@');
+		char* db=lsplit(host, '/');
+		char* pwd=lsplit(user, ':');
+		char* port=lsplit(host, ':');
 
 		char *options=lsplit(db, '?');
 
-		char *cstrBackwardCompAskServerToTranscode=0;
+		char* charset=0;
+		char* datestyle=0;
+
+		Connection& connection=*(Connection *)services.malloc(sizeof(Connection));
 
-		Connection& connection=*(Connection  *)services.malloc(sizeof(Connection));
 		*connection_ref=&connection;
 		connection.services=&services;
-		connection.cstrClientCharset=0;	
+		connection.client_charset=0;
+		connection.autocommit=false;
+		connection.with_default_transactions=false;
+		connection.standard_conforming_strings=true;
+
 		connection.conn=PQsetdbLogin(
 			(host&&strcasecmp(host, "local")==0)?NULL/* local Unix domain socket */:host, port, 
 			NULL, NULL, db, user, pwd);
+
 		if(!connection.conn)
 			services._throw("PQsetdbLogin failed");
-		if(PQstatus(connection.conn)!=CONNECTION_OK)  
+
+		if(PQstatus(connection.conn)!=CONNECTION_OK)
 			throwPQerror;
 
-		char *charset=0;
-		char *datestyle=0;
-		isDefaultTransaction = true;
-
-		while(options) {
-			if(char *key=lsplit(&options, '&')) {
-				if(*key) {
-					if(char *value=lsplit(key, '=')) {
-						if(strcmp(key, "ClientCharset" ) == 0) {
+		while(options){
+			if(char *key=lsplit(&options, '&')){
+				if(*key){
+					if(char *value=lsplit(key, '=')){
+						if(strcmp(key, "ClientCharset")==0){
 							toupper_str(value, value, strlen(value));
-							connection.cstrClientCharset=value;
-						} else if(strcasecmp(key, "charset")==0) { // left for backward compatibility, consider using ClientCharset
-							cstrBackwardCompAskServerToTranscode=value;
-						} else if(strcasecmp(key, "datestyle")==0) {
+							connection.client_charset=value;
+						} else if(strcasecmp(key, "charset")==0){
+							charset=value;
+						} else if(strcasecmp(key, "datestyle")==0){
 							datestyle=value;
-						} else if(strcmp(key, "WithoutDefaultTransaction")==0) {
-							if(strcmp(value, "1" ) == 0) {
-								isDefaultTransaction = false;
-							} else if(strcmp(value, "0" ) == 0) {
-								isDefaultTransaction = true;
-							} else {
-								services._throw("Bad WithoutDefaultTransaction option value. Only 0 or 1 are accepted." /*value*/);
+						} else if(strcasecmp(key, "autocommit")==0){
+							if(atoi(value)==1){
+								if(!connection.with_default_transactions)
+									services._throw("autocommit can be used only with_default_transaction enabled");
+								connection.autocommit=true;
 							}
+						} else if(strcmp(key, "with_default_transaction")==0){
+							if(atoi(value)==1)
+								connection.with_default_transactions=true;
+						} else if(strcmp(key, "WithoutDefaultTransaction")==0){
+							if(atoi(value)==0)
+								connection.with_default_transactions=true;
+						} else if(strcasecmp(key, "standard_conforming_strings")==0){
+							if(atoi(value)==0)
+								connection.standard_conforming_strings=false;
 						} else
 							services._throw("unknown connect option" /*key*/);
 					} else 
@@ -167,90 +207,135 @@ public:
 			}
 		}
 
-		if(connection.cstrClientCharset && cstrBackwardCompAskServerToTranscode)
-			services._throw("use 'ClientCharset' option only, "
-				"'charset' option is obsolete and should not be used with new 'ClientCharset' option");
-
-		if(cstrBackwardCompAskServerToTranscode) {
-			// set CLIENT_ENCODING
-			char statement[MAX_STRING]="set CLIENT_ENCODING="; // win
-			strncat(statement, cstrBackwardCompAskServerToTranscode, MAX_STRING);
+		if(charset){
+			char statement[MAX_STRING+1]="SET CLIENT_ENCODING=";
+			strncat(statement, charset, MAX_STRING);
 
-			execute_resultless(connection, statement);
+			_execute_cmd(connection, statement);
 		}
 
-		if(datestyle) {
-			// set DATESTYLE
-			char statement[MAX_STRING]="set DATESTYLE="; // ISO,SQL,Postgres,European,NonEuropean=US,German,DEFAULT=ISO
-			strncat(statement, charset, MAX_STRING);
+		if(datestyle){
+			char statement[MAX_STRING+1]="SET DATESTYLE=";
+			strncat(statement, datestyle, MAX_STRING);
 
-			execute_resultless(connection, statement);
+			_execute_cmd(connection, statement);
 		}
 
-		begin_transaction(connection);
+		_transaction_begin(connection);
 	}
-	void disconnect(void *aconnection) {
-		Connection& connection=*static_cast<Connection*>(aconnection);
 
-	    PQfinish(connection.conn);
+	void disconnect(void *aconnection){
+		Connection& connection=*static_cast<Connection*>(aconnection);
+		PQfinish(connection.conn);
 		connection.conn=0;
 	}
-	void commit(void *aconnection) {
-		execute_transaction_cmd(aconnection, "COMMIT");
+
+	void commit(void *aconnection){
+		Connection& connection=*static_cast<Connection*>(aconnection);
+		_transaction_commit(connection);
+		_transaction_begin(connection);
 	}
-	void rollback(void *aconnection) {
-		execute_transaction_cmd(aconnection, "ROLLBACK");
+
+	void rollback(void *aconnection){
+		Connection& connection=*static_cast<Connection*>(aconnection);
+		_transaction_rollback(connection);
+		_transaction_begin(connection);
 	}
 
 	bool ping(void *aconnection) {
 		Connection& connection=*static_cast<Connection*>(aconnection);
-
 		return PQstatus(connection.conn)==CONNECTION_OK;
 	}
 
-	const char* quote(
-		void *aconnection,
-		const char *from, unsigned int length) {
+	// charset here is services.request_charset(), not connection.client_charset
+	// thus we can't use the sql server quoting support
+	const char* quote(void *aconnection, const char *str, unsigned int length) 
+	{
 		Connection& connection=*static_cast<Connection*>(aconnection);
 
-		char *result=(char*)connection.services->malloc_atomic(length*2+1);
-		int err = 0;
-		PQescapeStringConn (connection.conn,
-                           result, from, length,
-                           &err);
+		const char* from;
+		const char* from_end=str+length;
+
+		size_t quoted=0;
+
+		if(connection.standard_conforming_strings){
+			for(from=str; from<from_end; from++){
+				if(*from=='\'')
+					quoted++;
+			}
+		} else {
+			for(from=str; from<from_end; from++){
+				switch (*from) {
+				case '\'':
+				case '\\':
+					quoted++;
+				}
+			}
+		}
+
+		if(!quoted)
+			return str;
+
+		char *result=(char*)connection.services->malloc_atomic(length + quoted + 1);
+		char *to = result;
+
+		if(connection.standard_conforming_strings){
+			for(from=str; from<from_end; from++){
+				if(*from=='\'')
+					*to++= '\''; // "'" -> "''"
+				*to++=*from;
+			}
+		} else {
+			for(from=str; from<from_end; from++){
+				switch (*from) {
+				case '\'': // "'" -> "''"
+					*to++= '\'';
+					break;
+				case '\\': // "\" -> "\\"
+					*to++='\\';
+					break;
+				}
+				*to++=*from;
+			}
+		}
+		
+		*to=0;
 		return result;
 	}
-	
+
 	void query(void *aconnection, 
-		const char *astatement, 
-		size_t placeholders_count, Placeholder* placeholders, 
-		unsigned long offset, unsigned long limit,
-		SQL_Driver_query_event_handlers& handlers) {
-//		_asm int 3;
+				const char *astatement, 
+				size_t placeholders_count, Placeholder* placeholders, 
+				unsigned long offset, unsigned long limit,
+				SQL_Driver_query_event_handlers& handlers
+	){
 		Connection& connection=*static_cast<Connection*>(aconnection);
-		const char* cstrClientCharset=connection.cstrClientCharset;
 		SQL_Driver_services& services=*connection.services;
 		PGconn *conn=connection.conn;
 
+		const char* client_charset=connection.client_charset;
+		const char* request_charset=services.request_charset();
+		bool transcode_needed=client_charset && strcmp(client_charset, request_charset)!=0;
+
 		const char** paramValues;
 		if(placeholders_count>0){
-			//services._throw("bind variables not supported (yet)");
-			int binds_size=sizeof(char) * placeholders_count;
+			int binds_size=sizeof(char)*placeholders_count;
 			paramValues = static_cast<const char**>(services.malloc_atomic(binds_size));
-			bind_parameters(placeholders_count, placeholders, paramValues, connection);
+			_bind_parameters(placeholders_count, placeholders, paramValues, connection, transcode_needed);
 		}
 
-		// transcode from $request:charset to connect-string?client_charset
-		if(cstrClientCharset) {
-			size_t transcoded_statement_size;
-			services.transcode(astatement, strlen(astatement),
-				astatement, transcoded_statement_size,
-				services.request_charset(),
-				cstrClientCharset);
+		size_t statement_size=0;
+		if(transcode_needed){
+			// transcode query from $request:charset to ?ClientCharset
+			statement_size=strlen(astatement);
+			services.transcode(astatement, statement_size,
+				astatement, statement_size,
+				request_charset,
+				client_charset);
 		}
 
-		const char *statement=preprocess_statement(connection,
-			astatement, offset, limit);
+		const char *statement=_preprocess_statement(connection, astatement, statement_size, offset, limit);
+		// error after prepare?
 
 		PGresult *res;
 		if(placeholders_count>0){
@@ -261,46 +346,53 @@ public:
 		if(!res) 
 			throwPQerror;
 
+		bool failed=false;
+		SQL_Error sql_error;
+
 		switch(PQresultStatus(res)) {
-		case PGRES_EMPTY_QUERY: 
-			PQclear_throw("no query");
-			break;
-		case PGRES_COMMAND_OK:
-			// empty result: insert|delete|update|...
-			PQclear(res);
-			return;
-		case PGRES_TUPLES_OK: 
-			break;	
-		default:
-			PQclear_throwPQerror;
-			break;
+			case PGRES_EMPTY_QUERY: 
+				PQclear_throw("no query");
+				break;
+			case PGRES_COMMAND_OK: // empty result: insert|delete|update|...
+				PQclear(res);
+				if(connection.autocommit)
+					commit(aconnection);
+				return;
+			case PGRES_TUPLES_OK: 
+				break;	
+			default:
+				PQclear_throwPQerror;
+				break;
 		}
 		
-		int column_count=PQnfields(res);
-		if(!column_count)
-			PQclear_throw("result contains no columns");
-
-		bool failed=false;
-		SQL_Error sql_error;
 #define CHECK(afailed) \
 		if(afailed) { \
 			failed=true; \
 			goto cleanup; \
 		}
 
-		for(int i=0; i<column_count; i++){
+		size_t column_count=PQnfields(res);
+		if(!column_count)
+			PQclear_throw("result contains no columns");
+
+		if(column_count>MAX_COLS)
+			column_count=MAX_COLS;
+
+		unsigned int column_types[MAX_COLS];
+
+		for(size_t i=0; i<column_count; i++){
+			column_types[i]=PQftype(res, i);
+
 			char *name=PQfname(res, i);
 			size_t length=strlen(name);
-			char* strm=(char*)services.malloc(length+1);
-			memcpy(strm, name, length+1);
-			const char* str=strm;
+			const char* str=strdup(services, name, length);
 
-			// transcode to $request:charset from connect-string?client_charset
-			if(cstrClientCharset) 
+			if(transcode_needed)
+				// transcode column name from ?ClientCharset to $request:charset
 				services.transcode(str, length,
 					str, length,
-					cstrClientCharset,
-					services.request_charset());
+					client_charset,
+					request_charset);
 
 			CHECK(handlers.add_column(sql_error, str, length));
 		}
@@ -310,61 +402,80 @@ public:
 		if(unsigned long row_count=(unsigned long)PQntuples(res))
 			for(unsigned long r=0; r<row_count; r++) {
 				CHECK(handlers.add_row(sql_error));
-				for(int i=0; i<column_count; i++){
-					const char *cell=PQgetvalue(res, r, i);
-					size_t length;
-					const char* str;
-					if(PQftype(res, i)==OIDOID) {
-						// ObjectID column, read object bytes
+				for(size_t i=0; i<column_count; i++){
+					char *cell=PQgetvalue(res, r, i);
 
-						char *error_pos=0;
-						Oid oid=cell?atoi(cell):0;
-						int fd=lo_open(conn, oid, INV_READ);
-						if(fd>=0) {
-							// seek to end
-							if(lo_lseek(conn, fd, 0, SEEK_END)<0)
-								PQclear_throwPQerror;
-							// get length
-							int size_tell=lo_tell(conn, fd);
-							if(size_tell<0)
-								PQclear_throwPQerror;
-							// seek to begin
-							if(lo_lseek(conn, fd, 0, SEEK_SET)<0)
-								PQclear_throwPQerror;
-							length=(size_t)size_tell;
-							if(length) {
-								// read 
-								char* strm=(char*)services.malloc(length+1);
-								if(!lo_read_ex(conn, fd, strm, size_tell))
-									PQclear_throw("lo_read can not read all bytes of object");
-								strm[length]=0;
-								str=strm;
-							} else
-								str=0;
-							if(lo_close(conn, fd)<0)
-								PQclear_throwPQerror;
-						} else
-							PQclear_throwPQerror;
-					} else {
-						// normal column, read it normally
-						length=(size_t)PQgetlength(res, r, i);
-						if(length) {
-							char* strm=(char*)services.malloc(length+1);
-							memcpy(strm, cell, length+1);
-							str=strm;
-						} else
-							str=0;
-					}
+					size_t length=0;
+					const char* str;
 
-					if(str && length) {
-						// transcode to $request:charset from connect-string?client_charset
-						if(cstrClientCharset)
-							services.transcode(str, length,
-								str, length,
-								cstrClientCharset,
-								services.request_charset());
+					switch(column_types[i]){
+						case BOOLOID:
+						case INT8OID:
+						case INT2OID:
+						case INT4OID:
+						case FLOAT4OID:
+						case FLOAT8OID:
+						case DATEOID:
+						case TIMEOID:
+						case TIMESTAMPOID:
+						case TIMESTAMPTZOID:
+						case TIMETZOID:
+						case NUMERICOID:
+							length=(size_t)PQgetlength(res, r, i);
+							str=length ? strdup(services, cell, length) : 0;
+							// transcode is never required for these types
+							break;
+						case OIDOID:
+							{
+								Oid oid=cell?atoi(cell):0;
+								int fd=lo_open(conn, oid, INV_READ);
+								if(fd>=0){
+									// seek to end
+									if(lo_lseek(conn, fd, 0, SEEK_END)<0)
+										PQclear_throwPQerror;
+									// get length
+									int size_tell=lo_tell(conn, fd);
+									if(size_tell<0)
+										PQclear_throwPQerror;
+									// seek to begin
+									if(lo_lseek(conn, fd, 0, SEEK_SET)<0)
+										PQclear_throwPQerror;
+									length=(size_t)size_tell;
+									if(length){
+										// read 
+										char* strm=(char*)services.malloc(length+1);
+										if(!lo_read_ex(conn, fd, strm, size_tell))
+											PQclear_throw("lo_read can not read all bytes of object");
+										strm[length]=0;
+										str=strm;
+										if(transcode_needed) {
+											// transcode cell value from ?ClientCharset to $request:charset
+											services.transcode(str, length,
+												str, length,
+												client_charset,
+												request_charset);
+										}
+									} else
+										str=0;
+									if(lo_close(conn, fd)<0)
+										PQclear_throwPQerror;
+								} else
+									PQclear_throwPQerror;
+								break;
+							}
+						default:
+							// normal column, read it normally
+							length=(size_t)PQgetlength(res, r, i);
+							str=length ? strdup(services, cell, length) : 0;
+							if(transcode_needed) {
+								// transcode cell value from ?ClientCharset to $request:charset
+								services.transcode(str, length,
+									str, length,
+									client_charset,
+									request_charset);
+							}
+							break;
 					}
-
 					CHECK(handlers.add_row_cell(sql_error, str, length));
 				}
 			}
@@ -372,86 +483,95 @@ cleanup:
 		PQclear(res);
 		if(failed)
 			services._throw(sql_error);
-	}
 
-private: // private funcs
+		if(connection.autocommit)
+			commit(aconnection);
+	}
 
-	void bind_parameters(
-		size_t placeholders_count, 
-		Placeholder* placeholders, 
-		const char** paramValues,
-		Connection& connection
-		) {
-		for(size_t i=0; i<placeholders_count; i++) {
+private:
+	void _bind_parameters(
+				size_t placeholders_count, 
+				Placeholder* placeholders, 
+				const char** paramValues,
+				Connection& connection,
+				bool transcode_needed
+	){
+		for(size_t i=0; i<placeholders_count; i++){
 			Placeholder& ph=placeholders[i];
-			size_t value_length;
-			if(connection.cstrClientCharset) {
+			if(transcode_needed){
 				size_t name_length;
 				connection.services->transcode(ph.name, strlen(ph.name),
 					ph.name, name_length,
 					connection.services->request_charset(),
-					connection.cstrClientCharset);
+					connection.client_charset);
 
 				if(ph.value) {
+					size_t value_length;
 					connection.services->transcode(ph.value, strlen(ph.value),
 						ph.value, value_length,
 						connection.services->request_charset(),
-						connection.cstrClientCharset);
+						connection.client_charset);
 				}
 			}
-			if( atoi(ph.name) <= 0 || atoi(ph.name) > placeholders_count) {
+			int name_number=atoi(ph.name);
+			if(name_number <= 0 || (size_t)name_number > placeholders_count)
 				connection.services->_throw("bad bind parameter key");
-			}
-			paramValues[atoi(ph.name)-1] = ph.value;
+
+			paramValues[name_number-1]=ph.value;
 		}
 	}
 	
 	
-	void execute_transaction_cmd(void *aconnection, const char *query) {
-		if(isDefaultTransaction)
-		{
-			Connection& connection=*static_cast<Connection*>(aconnection);
-			execute_resultless(connection, query);
-			begin_transaction(connection);
-		}
+	void _transaction_begin(Connection& connection){
+		_execute_transactions_cmd(connection, "BEGIN");
 	}
-	
-	/**
-		Executes a query and throws the result.
-	*/
-	void execute_resultless(const Connection& connection, const char *query) {
+
+	void _transaction_commit(Connection& connection){
+		_execute_transactions_cmd(connection, "COMMIT");
+	}
+
+	void _transaction_rollback(Connection& connection){
+		_execute_transactions_cmd(connection, "ROLLBACK");
+	}
+
+	void _execute_transactions_cmd(const Connection& connection, const char *query){
+		if(connection.with_default_transactions) // without ?with_default_transaction=1 user must execute BEGIN/COMMIT/ROLLBACK by himself
+			_execute_cmd(connection, query);
+	}
+
+	// executes a query and throw away the result.
+	void _execute_cmd(const Connection& connection, const char *query){
 		if(PGresult *res=PQexec(connection.conn, query))
-			PQclear(res); // throw out the result [don't need but must call]
+			PQclear(res); // throw away the result [don't need but must call]
 		else
 			throwPQerror;
 	}
 
-	void begin_transaction(Connection& connection) {
-		if(isDefaultTransaction)
-		{
-			execute_resultless(connection, "BEGIN");
-		}
-	}
-
-	const char *preprocess_statement(Connection& connection,
-		const char *astatement, unsigned long offset, unsigned long limit) {
+	const char *_preprocess_statement(
+					Connection& connection,
+					const char *astatement,
+					size_t statement_size,
+					unsigned long offset,
+					unsigned long limit
+	){
 		PGconn *conn=connection.conn;
 
-		size_t statement_size=strlen(astatement);
+		if(!statement_size)
+			statement_size=strlen(astatement);
 
 		char *result=(char *)connection.services->malloc(statement_size
-			+MAX_NUMBER*2+15 // limit # offset #
+			+MAX_NUMBER*2+15 // " limit # offset #"
 			+MAX_STRING // in case of short 'strings'
 			+1);
 		// offset & limit -> suffixes
 		const char *o;
-		if(offset || limit) {
+		if(offset || limit!=SQL_NO_LIMIT){
 			char *cur=result;
 			memcpy(cur, astatement, statement_size); cur+=statement_size;
-			if(limit)
-				cur+=snprintf(cur, 7+MAX_NUMBER, " limit %u", limit);
+			if(limit!=SQL_NO_LIMIT)
+				cur+=snprintf(cur, 7+MAX_NUMBER, " limit %lu", limit);
 			if(offset)
-				cur+=snprintf(cur, 8+MAX_NUMBER, " offset %u", offset);
+				cur+=snprintf(cur, 8+MAX_NUMBER, " offset %lu", offset);
 			o=result;
 		} else 
 			o=astatement;
@@ -461,7 +581,7 @@ private: // private funcs
 		while(*o) {
 			if(
 				o[0]=='/' &&
-				o[1]=='*' && 
+				o[1]=='*' &&
 				o[2]=='*') { // name start
 				const char* saved_o=o;
 				o+=3;
@@ -529,7 +649,7 @@ private: // lo_read/write exchancements
 		int size_op;
 		while(len && (size_op=lo_func(conn, fd, buf, min(LO_BUFSIZE, len)))>0) {
 			buf+=size_op;
-			len-=size_op;									
+			len-=size_op;
 		}
 		return len==0;
 	}
@@ -548,26 +668,25 @@ private: // conn client library funcs
 	typedef char *(*t_PQerrorMessage)(const PGconn* conn); t_PQerrorMessage PQerrorMessage;
 	typedef ConnStatusType (*t_PQstatus)(const PGconn *conn); t_PQstatus PQstatus;
 	typedef PGresult *(*t_PQexec)(PGconn *conn,
-	                 const char *query); t_PQexec PQexec;
-//PQexecParams
+						const char *query); t_PQexec PQexec;
 	typedef PGresult *(*t_PQexecParams)(
-					   PGconn *conn,
-					   const char *query, 
-					   int nParams,
-                       const Oid *paramTypes,
-                       const char * const *paramValues,
-                       const int *paramLengths,
-                       const int *paramFormats,
-                       int resultFormat); t_PQexecParams PQexecParams;
+						PGconn *conn,
+						const char *query, 
+						int nParams,
+						const Oid *paramTypes,
+						const char * const *paramValues,
+						const int *paramLengths,
+						const int *paramFormats,
+						int resultFormat); t_PQexecParams PQexecParams;
 
 	typedef ExecStatusType (*t_PQresultStatus)(const PGresult *res); t_PQresultStatus PQresultStatus;
 	typedef int (*t_PQgetlength)(const PGresult *res,
-					int tup_num,
-					int field_num); t_PQgetlength PQgetlength;
+						int tup_num,
+						int field_num); t_PQgetlength PQgetlength;
 	typedef char* (*t_PQgetvalue)(const PGresult *res,
-					 int tup_num,
-					 int field_num); t_PQgetvalue PQgetvalue;
-	typedef int (*t_PQntuples)(const PGresult *res); t_PQntuples PQntuples;
+						int tup_num,
+						int field_num); t_PQgetvalue PQgetvalue;
+	typedef int	(*t_PQntuples)(const PGresult *res); t_PQntuples PQntuples;
 	typedef char *(*t_PQfname)(const PGresult *res,
 						int field_index); t_PQfname PQfname;
 	typedef int (*t_PQnfields)(const PGresult *res); t_PQnfields PQnfields;
@@ -576,8 +695,8 @@ private: // conn client library funcs
 	typedef Oid	(*t_PQftype)(const PGresult *res, int field_num); t_PQftype PQftype;
 
 	typedef size_t (*t_PQescapeStringConn)(PGconn *conn,
-                           char *to, const char *from, size_t length,
-                           int *error); t_PQescapeStringConn PQescapeStringConn;
+						char *to, const char *from, size_t length,
+						int *error); t_PQescapeStringConn PQescapeStringConn;
 
 	typedef int	(*t_lo_open)(PGconn *conn, Oid lobjId, int mode); t_lo_open lo_open;
 	typedef int	(*t_lo_close)(PGconn *conn, int fd); t_lo_close lo_close;
@@ -593,11 +712,19 @@ private: // conn client library funcs
 private: // conn client library funcs linking
 
 	const char *dlink(const char *dlopen_file_spec) {
-		if(lt_dlinit())
-			return lt_dlerror();
-        lt_dlhandle handle=lt_dlopen(dlopen_file_spec);
-        if(!handle)
+		if(lt_dlinit()){
+			if(const char* result=lt_dlerror())
+				return result;
+			return "can not prepare to dynamic loading";
+		}
+
+		lt_dlhandle handle=lt_dlopen(dlopen_file_spec);
+
+		if(!handle){
+			if(const char* result=lt_dlerror())
+				return result;
 			return "can not open the dynamic link module";
+		}
 
 		#define DSLINK(name, action) \
 			name=(t_##name)lt_dlsym(handle, #name); \
@@ -629,8 +756,6 @@ private: // conn client library funcs li
 
 		return 0;
 	}
-
-	bool isDefaultTransaction;
 };
 
 extern "C" SQL_Driver *SQL_DRIVER_CREATE() {