corosync/exec/hdb.c

/*
 * Copyright (c) 2002-2004 MontaVista Software, Inc.
 *
 * All rights reserved.
 *
 * Author: Steven Dake (sdake@mvista.com)
 *
 * This software licensed under BSD license, the text of which follows:
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - Neither the name of the MontaVista Software, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "hdb.h"

enum SA_HANDLE_STATE {
	SA_HANDLE_STATE_EMPTY,
	SA_HANDLE_STATE_PENDINGREMOVAL,
	SA_HANDLE_STATE_ACTIVE
};

struct saHandle {
	int state;
	void *instance;
	int refCount;
};

SaErrorT
saHandleCreate (
	struct saHandleDatabase *handleDatabase,
	int instanceSize,
	unsigned int *handleOut)
{
	int handle;
	void *newHandles;
	int found = 0;
	void *instance;

	for (handle = 0; handle < handleDatabase->handleCount; handle++) {
		if (handleDatabase->handles[handle].state == SA_HANDLE_STATE_EMPTY) {
			found = 1;
			break;
		}
	}

	if (found == 0) {
		handleDatabase->handleCount += 1;
		newHandles = (struct saHandle *)realloc (handleDatabase->handles,
			sizeof (struct saHandle) * handleDatabase->handleCount);
		if (newHandles == 0) {
			return (SA_ERR_NO_MEMORY);
		}
		handleDatabase->handles = newHandles;
	}

	instance = malloc (instanceSize);
	if (instance == 0) {
		return (SA_ERR_NO_MEMORY);
	}
	memset (instance, 0, instanceSize);

	handleDatabase->handles[handle].state = SA_HANDLE_STATE_ACTIVE;

	handleDatabase->handles[handle].instance = instance;

	handleDatabase->handles[handle].refCount = 1;

	*handleOut = handle;

	return (SA_OK);
}


SaErrorT
saHandleDestroy (
	struct saHandleDatabase *handleDatabase,
	unsigned int handle)
{
	handleDatabase->handles[handle].state = SA_HANDLE_STATE_PENDINGREMOVAL;
	saHandleInstancePut (handleDatabase, handle);

	return (SA_OK);
}


SaErrorT
saHandleInstanceGet (
	struct saHandleDatabase *handleDatabase,
	unsigned int handle,
	void **instance)
{ 

	if (handle > handleDatabase->handleCount) {
		return (SA_ERR_BAD_HANDLE);
	}
	if (handleDatabase->handles[handle].state != SA_HANDLE_STATE_ACTIVE) {
		return (SA_ERR_BAD_HANDLE);
	}

	*instance = handleDatabase->handles[handle].instance;

	handleDatabase->handles[handle].refCount += 1;

	return (SA_OK);
}


SaErrorT
saHandleInstancePut (
	struct saHandleDatabase *handleDatabase,
	unsigned int handle)
{
	void *instance;

	handleDatabase->handles[handle].refCount -= 1;
	assert (handleDatabase->handles[handle].refCount >= 0);

	if (handleDatabase->handles[handle].refCount == 0) {
		instance = (handleDatabase->handles[handle].instance);
		if (handleDatabase->handleInstanceDestructor) {
			handleDatabase->handleInstanceDestructor (instance);
		}
		free (instance);
		memset (&handleDatabase->handles[handle], 0, sizeof (struct saHandle));
	}

	return (SA_OK);
}