/** * This file is part of license combination gpl version 3 license and eCos. * The corresponding license terms are below. * * gpl version 3 Licence: * * The file were developed during the student thesis "Datensammlung in Wireless * Sensor Networks fuer Autonomic Home NetworkingÒ of Thomas Kothmayr and is * included in the dissertation "Secure Data Transmission in Wireless * Sensor Networks" by Corinna Schmitt during employment at the Technische * UniversitŠt MŸnchen, Department Computer Science, Chair Network * Architectures and Services (Germany). * Copyright (C) 2013 * Authors: Thomas Kothmayr and Corinna Schmitt (schmitt[at]net.in.tum.de) * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, version 3 of the License * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . * * * eCos Licence: (http://ecos.sourceware.org) * * This file is part of eCos, the Embedded Configurable Operating System. * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, * 2007, 2008, 2009 Free Software Foundation, Inc. * * eCos is free software; you can redistribute it and/or modify it under * the terms of the GNU General Public License as published by the Free * Software Foundation; either version 3 any later version. * * eCos is distributed in the hope that it will be useful, but WITHOUT ANY * WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along * with eCos; if not, write to the Free Software Foundation, Inc., 51 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * * As a special exception, if other files instantiate templates or use * macros or inline functions from this file, or you compile this file and * link it with other works to produce a work based on this file, this file * does not by itself cause the resulting work to be covered by the GNU * General Public License. However the source code for this file must still * be made available in accordance with section (3) of the GNU General * Public License v2. * * This exception does not invalidate any other reasons why a work based on * this file might be covered by the GNU General Public License. * */ Interface: tos.interfaces.Resource

Interface: tos.interfaces.Resource

interface Resource

Please refer to TEP 108 for more information about this interface and its intended use.

The Resource interface can be used to gain access to shared resources. It is always offered as a parameterized interface, and its users gain access to the resource through some predefined arbitration policy.

Author:
Kevin Klues (klueska@cs.wustl.edu)
Version:
$Revision: 1.5 $
Date:
$Date: 2007/04/15 20:05:03 $

Commands
command error_t immediateRequest() Request immediate access to a shared resource.
command bool isOwner() Check if the user of this interface is the current owner of the Resource
command error_t release() Release a shared resource you previously acquired.
command error_t request() Request access to a shared resource.

Events
event void granted() You are now in control of the resource.

Commands - Details

immediateRequest

command error_t immediateRequest()

Request immediate access to a shared resource. You must call release() when you are done with it.

Returns:
SUCCESS When a request has been accepted.
FAIL The request cannot be fulfilled

isOwner

command bool isOwner()

Check if the user of this interface is the current owner of the Resource

Returns:
TRUE It is the owner
FALSE It is not the owner

release

command error_t release()

Release a shared resource you previously acquired.

Returns:
SUCCESS The resource has been released
FAIL You tried to release but you are not the owner of the resource
Note:
This command should never be called between putting in a request and waiting for a granted event. Doing so will result in a potential race condition. There are ways to guarantee that no race will occur, but they are clumsy and overly complicated. Since it doesn't logically make since to be calling release before receiving a granted event, we have opted to keep thing simple and warn you about the potential race.

request

command error_t request()

Request access to a shared resource. You must call release() when you are done with it.

Returns:
SUCCESS When a request has been accepted. The granted() event will be signaled once you have control of the resource.
EBUSY You have already requested this resource and a granted event is pending

Events - Details

granted

event void granted()

You are now in control of the resource.