var.c

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/*
 *	@file 	var.c
 *	@brief 	MPR Universal Variable Type
 *	@overview
 *
 *	@copy	default.m
 *	
 *	Copyright (c) Mbedthis Software LLC, 2003-2005. All Rights Reserved.
 *	Copyright (c) Michael O'Brien, 1994-1995. All Rights Reserved.
 *	
 *	This software is distributed under commercial and open source licenses.
 *	You may use the GPL open source license described below or you may acquire 
 *	a commercial license from Mbedthis Software. You agree to be fully bound 
 *	by the terms of either license. Consult the LICENSE.TXT distributed with 
 *	this software for full details.
 *	
 *	This software is open source; 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 2 of the License, or (at your 
 *	option) any later version. See the GNU General Public License for more 
 *	details at: http://www.mbedthis.com/downloads/gplLicense.html
 *	
 *	This program is distributed WITHOUT ANY WARRANTY; without even the 
 *	implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 *	
 *	This GPL license does NOT permit incorporating this software into 
 *	proprietary programs. If you are unable to comply with the GPL, you must
 *	acquire a commercial license to use this software. Commercial licenses 
 *	for this software and support services are available from Mbedthis 
 *	Software at http://www.mbedthis.com 
 *	
 *	@end
 */

/******************************* Documentation ********************************/

/*
 *	This module is NOT multithreaded. 
 *
 *	Properties are variables that are stored in an object type variable.
 *	Properties can be primitive data types, other objects or functions.
 *	Properties are indexed by a character name.
 */

/********************************** Includes **********************************/

#include	"var.h"

/*********************************** Locals ***********************************/
#if VAR_DEBUG

static MprProperties	objectList;			/* Dummy head of objects list */
static int				objectCount = -1;	/* Count of objects */

#endif
/***************************** Forward Declarations ***************************/

static int 		adjustRefCount(MprProperties *pp, int adj);
static int		adjustVarRefCount(MprVar *vp, int adj);
static MprVar 	*allocProperty(const char *propertyName);
static void 	copyVarCore(MprVar *dest, MprVar *src, int copyDepth);
static MprProperties 
				*createProperties(const char *name, int hashSize);
static bool 	freeVar(MprVar *vp, int force);
static bool 	freeVarStorage(MprVar *vp, int force);
static MprVar	*getObjChain(MprProperties *pp, const char *property);
static int		hash(MprProperties *pp, const char *property);
static bool		releaseProperties(MprProperties *pp, int force);

/*********************************** Code *************************************/
/*
 *	Destroy a variable and all referenced variables. Release any referenced 
 *	object regardless of whether other users still have references. Be VERY
 *	careful using this routine. 
 *
 *	Return TRUE if the underlying data is freed. Objects may not be freed if 
 *	there are other users of the object.
 */

bool mprDestroyAllVars(MprVar *vp)
{
	mprAssert(vp);

	if (vp->trigger) {
		if ((vp->trigger)(MPR_VAR_DELETE, vp->parentProperties, vp, 0, 0) 
				== MPR_TRIGGER_ABORT) {
			return 0;
		}
	}

	/*
	 *	Free the actual value. If this var refers to an object, we will 
	 *	recurse through all the properties freeing all vars.
	 */
	return freeVar(vp, 1);
}

/******************************************************************************/
/*
 *	Destroy a variable. Release any referenced object (destroy if no other
 *	users are referencing).
 *
 *	Return TRUE if the underlying data is freed. Objects may not be freed if 
 *	there are other users of the object.
 */

bool mprDestroyVar(MprVar *vp)
{
	mprAssert(vp);

	if (vp->trigger) {
		if ((vp->trigger)(MPR_VAR_DELETE, vp->parentProperties, vp, 0, 0) 
				== MPR_TRIGGER_ABORT) {
			return 0;
		}
	}

	/*
	 *	Free the actual value. If this var refers to an object, we will 
	 *	recurse through all the properties freeing all that have no other
	 *	references.
	 */
	return freeVar(vp, 0);
}

/******************************************************************************/
/*
 *	Free the value in a variable for primitive types. Release objects.
 *
 *	Return TRUE if the underlying data is freed. Objects may not be freed if 
 *	there are other users of the object.
 */

static bool freeVar(MprVar *vp, int force)
{
	bool	freed;

	mprAssert(vp);

	freed = freeVarStorage(vp, force);

	mprFree(vp->name);
	mprFree(vp->fullName);

	if (vp->allocatedVar) {
		mprFree(vp);
	} else {
		vp->name = 0;
		vp->fullName = 0;
		vp->type = MPR_TYPE_UNDEFINED;
	}
	return freed;
}

/******************************************************************************/
/*
 *	Free the value in a variable for primitive types. Release objects.
 *
 *	Return TRUE if the underlying data is freed. Objects may not be freed if 
 *	there are other users of the object.
 */

static bool freeVarStorage(MprVar *vp, int force)
{
	MprArray	*argList;
	bool		freed;
	int			i;

	freed = 1;
	mprAssert(vp);

	switch (vp->type) {
	default:
		break;

	case MPR_TYPE_STRING:
		if (vp->allocatedData && vp->string != 0) {
			mprFree(vp->string);
			vp->string = 0;
			vp->allocatedData = 0;
		}
		break;

	case MPR_TYPE_PTR:
		if (vp->allocatedData) {
			vp->allocatedData = 0;
			mprFree(vp->ptr);
		}
		break;

	case MPR_TYPE_OBJECT:
#if VAR_DEBUG
		/*
		 *	Recurse through all properties and release / delete. Release the 
		 *	properties hash table.
		 */
		if (vp->properties->refCount > 1) {
			mprLog(7, "freeVar: ACT \"%s\", 0x%x, ref %d, force %d\n", 
				vp->name, vp->properties, vp->properties->refCount, force);
		} else {
			mprLog(7, "freeVar: DEL \"%s\", 0x%x, ref %d, force %d\n", 
				vp->name, vp->properties, vp->properties->refCount, force);
		}
#endif
		if (vp->allocatedData) {
			freed = releaseProperties(vp->properties, force);
		}
		vp->properties = 0;
		break;

	case MPR_TYPE_FUNCTION:
		if (vp->allocatedData) {
			argList = vp->function.args;
			for (i = 0; i < argList->max; i++) {
				if (argList->handles[i] != 0) {
					mprFree(argList->handles[i]);
				}
			}
			mprDestroyArray(argList);
			vp->function.args = 0;
			mprFree(vp->function.body);
			vp->function.body = 0;
		}
		break;
	}

	vp->type = MPR_TYPE_UNDEFINED;
	return freed;
}

/******************************************************************************/
/*
 *	Adjust the object reference count and return the currrent count of 
 *	users.
 */

static int adjustVarRefCount(MprVar *vp, int adj)
{
	mprAssert(vp);

	if (vp->type != MPR_TYPE_OBJECT) {
		mprAssert(vp->type == MPR_TYPE_OBJECT);
		return 0;
	}
	return adjustRefCount(vp->properties, adj);
}

/******************************************************************************/
/*
 *	Get the object reference count 
 */

int mprGetVarRefCount(MprVar *vp)
{
	mprAssert(vp);

	if (vp->type != MPR_TYPE_OBJECT) {
		mprAssert(vp->type == MPR_TYPE_OBJECT);
		return 0;
	}
	return adjustRefCount(vp->properties, 0);
}

/******************************************************************************/
/*
 *	Update the variable's name
 */

void mprSetVarName(MprVar *vp, char *name)
{
	mprAssert(vp);

	mprFree(vp->name);
	vp->name = mprStrdup(name);
}

/******************************************************************************/
/*
 *	Append to the variable's full name
 */

void mprSetVarFullName(MprVar *vp, char *name)
{
#if VAR_DEBUG
	mprAssert(vp);

	mprFree(vp->fullName);
	vp->fullName = mprStrdup(name);
	if (vp->type == MPR_TYPE_OBJECT) {
		if (strcmp(vp->properties->name, "this") == 0) {
			mprStrcpy(vp->properties->name, sizeof(vp->properties->name), name);
		}
	}
#endif
}

/******************************************************************************/
/*
 *	Make a var impervious to recursive forced deletes. 
 */

void mprSetVarDeleteProtect(MprVar *vp, int deleteProtect)
{
	mprAssert(vp);

	if (vp->type == MPR_TYPE_OBJECT && vp->properties) {
		vp->properties->deleteProtect = deleteProtect;
	}
}

/******************************************************************************/
/*
 *	Make a variable readonly. Can still be deleted.
 */

void mprSetVarReadonly(MprVar *vp, int readonly)
{
	mprAssert(vp);

	vp->readonly = readonly;
}

/******************************************************************************/

MprVarTrigger mprAddVarTrigger(MprVar *vp, MprVarTrigger fn)
{
	MprVarTrigger oldTrigger;

	mprAssert(vp);
	mprAssert(fn);

	oldTrigger = vp->trigger;
	vp->trigger = fn;
	return oldTrigger;
}

/******************************************************************************/

MprType mprGetVarType(MprVar *vp)
{
	mprAssert(vp);

	return vp->type;
}

/******************************************************************************/
/********************************** Properties ********************************/
/******************************************************************************/
/*
 *	Create a property in an object with a defined value. If the property 
 *	already exists in the object, then just write its value.
 */

MprVar *mprCreateProperty(MprVar *obj, const char *propertyName, 
	MprVar *newValue)
{
	MprVar	*prop, *last;
	int		bucketIndex;

	mprAssert(obj);
	mprAssert(propertyName && *propertyName);

	if (obj->type != MPR_TYPE_OBJECT) {
		mprAssert(obj->type == MPR_TYPE_OBJECT);
		return 0;
	}

	/*
	 *	See if property already exists and locate the bucket to hold the
	 *	property reference.
	 */
	last = 0;
	bucketIndex = hash(obj->properties, propertyName);
	prop = obj->properties->buckets[bucketIndex];

	/*
	 *	Find the property in the hash chain if it exists
 	 */
	for (last = 0; prop; last = prop, prop = prop->forw) {
		if (prop->name[0] == propertyName[0] && 
				strcmp(prop->name, propertyName) == 0) {
			break;
		}
	}

	if (prop) {
		/*	FUTURE -- remove. Just for debug. */
		mprAssert(prop == 0);
		mprLog(0, "Attempting to create property %s in object %s\n",
			propertyName, obj->name);
		return 0;
	}

	if (obj->trigger) {
		if ((obj->trigger)(MPR_VAR_CREATE_PROPERTY, obj->properties, prop, 
				newValue, 0) == MPR_TRIGGER_ABORT) {
			return 0;
		}
	}

	/*
 	 *	Create a new property
	 */
	prop = allocProperty(propertyName);
	if (prop == 0) {
		mprAssert(prop);
		return 0;
	}

	copyVarCore(prop, newValue, MPR_SHALLOW_COPY);

	prop->bucketIndex = bucketIndex;
	if (last) {
		last->forw = prop;
	} else {
		obj->properties->buckets[bucketIndex] = prop;
	}
	prop->parentProperties = obj->properties;

	/*
 	 *	Update the item counts 
	 */
	obj->properties->numItems++;
	if (! mprVarIsFunction(prop->type)) {
		obj->properties->numDataItems++;
	}

	return prop;
}

/******************************************************************************/
/*
 *	Create a property in an object with a defined value. If the property 
 *	already exists in the object, then just write its value. Same as 
 *	mprCreateProperty except that the new value is passed by value rather than
 *	by pointer.
 */

MprVar *mprCreatePropertyValue(MprVar *obj, const char *propertyName, 
	MprVar newValue)
{
	return mprCreateProperty(obj, propertyName, &newValue);
}

/******************************************************************************/
/*
 *	Create a new property
 */

static MprVar *allocProperty(const char *propertyName)
{
	MprVar		*prop;

	prop = (MprVar*) mprMalloc(sizeof(MprVar));
	if (prop == 0) {
		mprAssert(prop);
		return 0;
	}
	memset(prop, 0, sizeof(MprVar));
	prop->allocatedVar = 1;
	prop->name = mprStrdup(propertyName);
	prop->forw = (MprVar*) 0;

	return prop;
}

/******************************************************************************/
/*
 *	Update a property in an object with a defined value. Create the property
 *	if it doesn not already exist.
 */

MprVar *mprSetProperty(MprVar *obj, const char *propertyName, MprVar *newValue)
{
	MprVar	*prop, triggerValue;
	int		rc;

	mprAssert(obj);
	mprAssert(propertyName && *propertyName);
	mprAssert(obj->type == MPR_TYPE_OBJECT);

	if (obj->type != MPR_TYPE_OBJECT) {
		mprAssert(0);
		return 0;
	}

	prop = mprGetProperty(obj, propertyName, 0);
	if (prop == 0) {
		return mprCreateProperty(obj, propertyName, newValue);
	}

	if (obj->trigger) {
		/* 
		 *	Call the trigger before the update and pass it the new value.
		 */
		triggerValue = *newValue;
		triggerValue.allocatedVar = 0;
		triggerValue.allocatedData = 0;
		rc = (obj->trigger)(MPR_VAR_WRITE, obj->properties, obj, 
				&triggerValue, 0);
		if (rc == MPR_TRIGGER_ABORT) {
			return 0;

		} else if (rc == MPR_TRIGGER_USE_NEW_VALUE) {
			/*
			 *	Trigger must copy to triggerValue a variable that is not
			 *	a structure copy of the existing data.
			 */
			copyVarCore(prop, &triggerValue, MPR_SHALLOW_COPY);
			mprDestroyVar(&triggerValue);
			return prop;
		}
	}
	copyVarCore(prop, newValue, MPR_SHALLOW_COPY);
	return prop;
}

/******************************************************************************/
/*
 *	Update a property in an object with a defined value. Create the property
 *	if it does not already exist. Same as mprSetProperty except that the 
 *	new value is passed by value rather than by pointer.
 */

MprVar *mprSetPropertyValue(MprVar *obj, const char *propertyName, 
	MprVar newValue)
{
	return mprSetProperty(obj, propertyName, &newValue);
}

/******************************************************************************/
/*
 *	Delete a property from this object
 */

int mprDeleteProperty(MprVar *obj, const char *property)
{
	MprVar		*prop, *last;
	char		*cp;
	int			bucketIndex;

	mprAssert(obj);
	mprAssert(property && *property);
	mprAssert(obj->type == MPR_TYPE_OBJECT);

	if (obj->type != MPR_TYPE_OBJECT) {
		mprAssert(obj->type == MPR_TYPE_OBJECT);
		return 0;
	}

	last = 0;
	bucketIndex = hash(obj->properties, property);
	if ((prop = obj->properties->buckets[bucketIndex]) != 0) {
		for ( ; prop; prop = prop->forw) {