odbcdbc.c

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/*
 * The contents of this file are subject to the MonetDB Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://monetdb.cwi.nl/Legal/MonetDBLicense-1.1.html
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is the MonetDB Database System.
 *
 * The Initial Developer of the Original Code is CWI.
 * Portions created by CWI are Copyright (C) 1997-2007 CWI.
 * All Rights Reserved.
 */

/*
 * This code was created by Peter Harvey (mostly during Christmas 98/99).
 * This code is LGPL. Please ensure that this message remains in future
 * distributions and uses of this code (thats about all I get out of it).
 * - Peter Harvey [e-mail]
 * 
 * This file has been modified for the MonetDB project.  See the file
 * Copyright in this directory for more information.
 */

/**********************************************
 * ODBCDbc.c
 *
 * Description:
 * This file contains the functions which operate on
 * ODBC connection structures/objects (see ODBCDbc.h).
 *
 * Author: Martin van Dinther
 * Date  : 30 aug 2002
 *
 **********************************************/

#include "ODBCGlobal.h"
#include "ODBCDbc.h"

#define ODBC_DBC_MAGIC_NR  1365	/* for internal sanity check only */


/*
 * Creates a new allocated ODBCDbc object and initializes it.
 *
 * Precondition: none
 * Postcondition: returns a new ODBCDbc object
 */
ODBCDbc *
newODBCDbc(ODBCEnv *env)
{
	ODBCDbc *dbc;

	assert(env);

	dbc = (ODBCDbc *) malloc(sizeof(ODBCDbc));
	if (dbc == NULL) {
		/* Memory allocation error */
		addEnvError(env, "HY001", NULL, 0);
		return NULL;
	}
	assert(dbc);

	dbc->Env = env;
	dbc->Error = NULL;
	dbc->RetrievedErrors = 0;

	dbc->dsn = NULL;
	dbc->uid = NULL;
	dbc->pwd = NULL;
	dbc->host = NULL;
	dbc->port = 0;
	dbc->dbname = NULL;

	dbc->Connected = 0;
	dbc->sql_attr_autocommit = SQL_AUTOCOMMIT_ON;	/* default is autocommit */
	dbc->mid = NULL;
	dbc->Mdebug = 0;

	dbc->FirstStmt = NULL;

	/* add this dbc to start of the administrative linked dbc list */
	dbc->next = env->FirstDbc;
	env->FirstDbc = dbc;

	dbc->Type = ODBC_DBC_MAGIC_NR;	/* set it valid */

	return dbc;
}


/*
 * Check if the connection handle is valid.
 * Note: this function is used internally by the driver to assert legal
 * and save usage of the handle and prevent crashes as much as possible.
 *
 * Precondition: none
 * Postcondition: returns 1 if it is a valid connection handle,
 * 	returns 0 if is invalid and thus an unusable handle.
 */
int
isValidDbc(ODBCDbc *dbc)
{
#ifdef ODBCDEBUG
	if (!(dbc && dbc->Type == ODBC_DBC_MAGIC_NR))
		ODBCLOG("dbc " PTRFMT ": not a valid connection handle\n", PTRFMTCAST dbc);
#endif
	return dbc && dbc->Type == ODBC_DBC_MAGIC_NR;
}



/*
 * Creates and adds an error msg object to the end of the error list of
 * this ODBCDbc struct.
 * When the errMsg is NULL and the SQLState is an ISO SQLState the
 * standard ISO message text for the SQLState is used as message.
 *
 * Precondition: dbc must be valid. SQLState and errMsg may be NULL.
 */
void
addDbcError(ODBCDbc *dbc, const char *SQLState, const char *errMsg, int nativeErrCode)
{
	ODBCError *error = NULL;

#ifdef ODBCDEBUG
	ODBCLOG("addDbcError " PTRFMT " %s %s %d\n", PTRFMTCAST dbc, SQLState, errMsg ? errMsg : getStandardSQLStateMsg(SQLState), nativeErrCode);
#endif
	assert(isValidDbc(dbc));

	error = newODBCError(SQLState, errMsg, nativeErrCode);
	appendODBCError(&dbc->Error, error);
}


/*
 * Extracts an error object from the error list of this ODBCDbc struct.
 * The error object itself is removed from the error list.
 * The caller is now responsible for freeing the error object memory.
 *
 * Precondition: dbc and error must be valid
 * Postcondition: returns a ODBCError object or null when no error is available.
 */
ODBCError *
getDbcError(ODBCDbc *dbc)
{
	assert(isValidDbc(dbc));
	return dbc->Error;
}


/*
 * Destroys the ODBCDbc object including its own managed data.
 *
 * Precondition: dbc must be valid, inactive (not connected) and
 * no ODBCStmt (or ODBCDesc) objects may refer to this dbc.
 * Postcondition: dbc is completely destroyed, dbc handle is become invalid.
 */
void
destroyODBCDbc(ODBCDbc *dbc)
{
	assert(isValidDbc(dbc));
	assert(!dbc->Connected);
	assert(dbc->FirstStmt == NULL);

	/* first set this object to invalid */
	dbc->Type = 0;

	/* remove this dbc from the env */
	assert(dbc->Env);
	assert(dbc->Env->FirstDbc);
	{
		/* search for this dbc in the list */
		ODBCDbc *tmp_dbc = (ODBCDbc *) dbc->Env->FirstDbc;
		ODBCDbc *prv_dbc = NULL;

		while ((tmp_dbc != NULL) && (tmp_dbc != dbc)) {
			prv_dbc = tmp_dbc;
			tmp_dbc = tmp_dbc->next;
		}

		assert(tmp_dbc == dbc);	/* we must have found it */

		/* now remove it from the linked list */
		if (prv_dbc != NULL) {
			prv_dbc->next = dbc->next;
		} else {
			dbc->Env->FirstDbc = dbc->next;
		}
	}

	/* cleanup own managed data */
	deleteODBCErrorList(&dbc->Error);
	if (dbc->dsn)
		free(dbc->dsn);
	if (dbc->uid)
		free(dbc->uid);
	if (dbc->pwd)
		free(dbc->pwd);
	if (dbc->host)
		free(dbc->host);
	if (dbc->dbname)
		free(dbc->dbname);

	free(dbc);
}