/*
 * Copyright (c) 2003-2004 Apple Computer, Inc. All Rights Reserved.
 * 
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */


//
// transwalkers - server side transition data walking support
//
// These are data walker operators for securely marshaling and unmarshaling
// data structures across IPC. They are also in charge of fixing byte order
// inconsistencies between server and clients.
//
#include <transwalkers.h>
	

using LowLevelMemoryUtilities::increment;
using LowLevelMemoryUtilities::difference;


bool flipClient()
{
	return Server::process().byteFlipped();
}


//
// CheckingRelocateWalkers
//
CheckingReconstituteWalker::CheckingReconstituteWalker(void *ptr, void *base, size_t size, bool flip)
	: mBase(base), mFlip(flip)
{
	if (mFlip)
		Flippers::flip(mBase);	// came in reversed; fix for base use
	mOffset = difference(ptr, mBase);
	mLimit = increment(mBase, size);
}


//
// Relocation support
//
void relocate(Context &context, void *base, Context::Attr *attrs, uint32 attrSize)
{
	flip(context);
	CheckingReconstituteWalker relocator(attrs, base, attrSize, flipClient());
	context.ContextAttributes = attrs;	// fix context->attr vector link
	for (uint32 n = 0; n < context.attributesInUse(); n++)
		walk(relocator, context[n]);
}


//
// Outbound flipping support
//
FlipWalker::~FlipWalker()
{
	for (set<Flipper>::const_iterator it = mFlips.begin(); it != mFlips.end(); it++)
		delete it->impl;
}

void FlipWalker::doFlips(bool active)
{
	if (active) {
		secdebug("flipwalkers", "starting outbound flips");
		for (set<Flipper>::const_iterator it = mFlips.begin(); it != mFlips.end(); it++)
			it->impl->flip();
		secdebug("flipwalkers", "outbound flips done");
	}
}


//
// Choose a Database from a choice of two sources, giving preference
// to persistent stores and to earlier sources.
//
Database *pickDb(Database *db1, Database *db2)
{
	// persistent db1 always wins
	if (db1 && !db1->transient())
		return db1;
	
	// persistent db2 is next choice
	if (db2 && !db2->transient())
		return db2;
	
	// pick any existing transient database
	if (db1)
		return db1;
	if (db2)
		return db2;
	
	// none at all. use the canonical transient store
	return Server::optionalDatabase(noDb);
}



void fixDbAttributes (CssmDbAttributeData &data)
{
	/*
		NOTE TO FUTURE MAINTAINERS OF THIS CODE:
		
		This code is called by two different routines; the relocation walker on the input attributes, and flips
		on the output attributtes.  This is bad, because the relocation walker flips the Info data structure,
		and flips does not.  We could fix this in flips, but flips is a template and does different things
		depending on what its parameters are.  As a result, the best place to do this is here.
	*/

	// pull this data out first, so that it is unperverted once the flip occurs
	unsigned limit = data.size ();
	unsigned format = data.format ();
	CssmData* values = data.values ();
	
	// flip if it is safe to do so
	if (format > CSSM_DB_ATTRIBUTE_FORMAT_COMPLEX) // is the format screwed up?
	{
		flip (data.info ());
		limit = data.size ();
		format = data.format ();
		values = data.values ();
	}
	
	unsigned i;

	for (i = 0; i < limit; ++i)
	{
		switch (format)
		{
			case CSSM_DB_ATTRIBUTE_FORMAT_UINT32:
				Flippers::flip(*(uint32*) values[i].data ());
				break;
			
			case CSSM_DB_ATTRIBUTE_FORMAT_MULTI_UINT32:
			{
				CssmData& d = values[i];
				int numValues = d.length() / sizeof (UInt32);
				int j;
				UInt32* v = (UInt32*) d.data();
				for (j = 0; j < numValues; ++j)
				{
					Flippers::flip (v[j]);
				}
			}
			break;
		}
	}
}



void fixDbAttributes (CssmQuery &query)
{
	unsigned i;
	unsigned numItems = query.size ();
	for (i = 0; i < numItems; ++i)
	{
		fixDbAttributes(query.predicates()[i].attribute());
	}
}



void fixDbAttributes (CssmDbRecordAttributeData &data)
{
	unsigned i;
	unsigned numItems = data.size ();
	for (i = 0; i < numItems; ++i)
	{
		fixDbAttributes(data.attributes()[i]);
	}
}