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nsCompositeDataSource.cpp
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nsCompositeDataSource.cpp
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla 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://www.mozilla.org/MPL/
*
* 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 mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Ramanathan Guha <guha@netscape.com>
* Chris Waterson <waterson@netscape.com
* Pierre Phaneuf <pp@ludusdesign.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
A simple composite data source implementation. A composit data
source is just a strategy for combining individual data sources into
a collective graph.
1) A composite data source holds a sequence of data sources. The set
of data sources can be specified during creation of the
database. Data sources can also be added/deleted from a database
later.
2) The aggregation mechanism is based on simple super-positioning of
the graphs from the datasources. If there is a conflict (i.e.,
data source A has a true arc from foo to bar while data source B
has a false arc from foo to bar), the data source that it earlier
in the sequence wins.
The implementation below doesn't really do this and needs to be
fixed.
*/
#include "xpcom-config.h"
#include NEW_H
#include "nsCOMPtr.h"
#include "nsIComponentManager.h"
#include "nsIEnumerator.h"
#include "nsIRDFCompositeDataSource.h"
#include "nsIRDFNode.h"
#include "nsIRDFObserver.h"
#include "nsIRDFRemoteDataSource.h"
#include "nsFixedSizeAllocator.h"
#include "nsTArray.h"
#include "nsCOMArray.h"
#include "nsArrayEnumerator.h"
#include "nsXPIDLString.h"
#include "rdf.h"
#include "nsCycleCollectionParticipant.h"
#include "nsEnumeratorUtils.h"
#ifdef NS_DEBUG
#include "prlog.h"
#include "prprf.h"
#include <stdio.h>
PRLogModuleInfo* nsRDFLog = nsnull;
#endif
static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
//----------------------------------------------------------------------
//
// CompositeDataSourceImpl
//
class CompositeEnumeratorImpl;
class CompositeArcsInOutEnumeratorImpl;
class CompositeAssertionEnumeratorImpl;
class CompositeDataSourceImpl : public nsIRDFCompositeDataSource,
public nsIRDFObserver
{
public:
CompositeDataSourceImpl(void);
CompositeDataSourceImpl(char** dataSources);
// nsISupports interface
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(CompositeDataSourceImpl,
nsIRDFCompositeDataSource)
// nsIRDFDataSource interface
NS_DECL_NSIRDFDATASOURCE
// nsIRDFCompositeDataSource interface
NS_DECL_NSIRDFCOMPOSITEDATASOURCE
// nsIRDFObserver interface
NS_DECL_NSIRDFOBSERVER
PRBool HasAssertionN(int n, nsIRDFResource* source,
nsIRDFResource* property,
nsIRDFNode* target,
PRBool tv);
protected:
nsCOMArray<nsIRDFObserver> mObservers;
nsCOMArray<nsIRDFDataSource> mDataSources;
PRBool mAllowNegativeAssertions;
PRBool mCoalesceDuplicateArcs;
PRInt32 mUpdateBatchNest;
nsFixedSizeAllocator mAllocator;
virtual ~CompositeDataSourceImpl() {}
friend class CompositeEnumeratorImpl;
friend class CompositeArcsInOutEnumeratorImpl;
friend class CompositeAssertionEnumeratorImpl;
};
//----------------------------------------------------------------------
//
// CompositeEnumeratorImpl
//
class CompositeEnumeratorImpl : public nsISimpleEnumerator
{
// nsISupports
NS_DECL_ISUPPORTS
// nsISimpleEnumerator interface
NS_DECL_NSISIMPLEENUMERATOR
// pure abstract methods to be overridden
virtual nsresult
GetEnumerator(nsIRDFDataSource* aDataSource, nsISimpleEnumerator** aResult) = 0;
virtual nsresult
HasNegation(nsIRDFDataSource* aDataSource, nsIRDFNode* aNode, PRBool* aResult) = 0;
virtual void Destroy() = 0;
protected:
CompositeEnumeratorImpl(CompositeDataSourceImpl* aCompositeDataSource,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs);
virtual ~CompositeEnumeratorImpl();
CompositeDataSourceImpl* mCompositeDataSource;
nsISimpleEnumerator* mCurrent;
nsIRDFNode* mResult;
PRInt32 mNext;
nsAutoTArray<nsCOMPtr<nsIRDFNode>, 8> mAlreadyReturned;
PRPackedBool mAllowNegativeAssertions;
PRPackedBool mCoalesceDuplicateArcs;
};
CompositeEnumeratorImpl::CompositeEnumeratorImpl(CompositeDataSourceImpl* aCompositeDataSource,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs)
: mCompositeDataSource(aCompositeDataSource),
mCurrent(nsnull),
mResult(nsnull),
mNext(0),
mAllowNegativeAssertions(aAllowNegativeAssertions),
mCoalesceDuplicateArcs(aCoalesceDuplicateArcs)
{
NS_ADDREF(mCompositeDataSource);
}
CompositeEnumeratorImpl::~CompositeEnumeratorImpl(void)
{
NS_IF_RELEASE(mCurrent);
NS_IF_RELEASE(mResult);
NS_RELEASE(mCompositeDataSource);
}
NS_IMPL_ADDREF(CompositeEnumeratorImpl)
NS_IMPL_RELEASE_WITH_DESTROY(CompositeEnumeratorImpl, Destroy())
NS_IMPL_QUERY_INTERFACE1(CompositeEnumeratorImpl, nsISimpleEnumerator)
NS_IMETHODIMP
CompositeEnumeratorImpl::HasMoreElements(PRBool* aResult)
{
NS_PRECONDITION(aResult != nsnull, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
nsresult rv;
// If we've already queued up a next target, then yep, there are
// more elements.
if (mResult) {
*aResult = PR_TRUE;
return NS_OK;
}
// Otherwise, we'll need to find a next target, switching cursors
// if necessary.
for ( ; mNext < mCompositeDataSource->mDataSources.Count(); ++mNext) {
if (! mCurrent) {
// We don't have a current enumerator, so create a new one on
// the next data source.
nsIRDFDataSource* datasource =
mCompositeDataSource->mDataSources[mNext];
rv = GetEnumerator(datasource, &mCurrent);
if (NS_FAILED(rv)) return rv;
if (rv == NS_RDF_NO_VALUE)
continue;
NS_ASSERTION(mCurrent != nsnull, "you're always supposed to return an enumerator from GetEnumerator, punk.");
if (! mCurrent)
continue;
}
do {
PRInt32 i;
PRBool hasMore;
rv = mCurrent->HasMoreElements(&hasMore);
if (NS_FAILED(rv)) return rv;
// Is the current enumerator depleted?
if (! hasMore) {
NS_RELEASE(mCurrent);
break;
}
// Even if the current enumerator has more elements, we still
// need to check that the current element isn't masked by
// a negation in an earlier data source.
// "Peek" ahead and pull out the next target.
nsCOMPtr<nsISupports> result;
rv = mCurrent->GetNext(getter_AddRefs(result));
if (NS_FAILED(rv)) return rv;
rv = result->QueryInterface(NS_GET_IID(nsIRDFNode), (void**) &mResult);
if (NS_FAILED(rv)) return rv;
if (mAllowNegativeAssertions)
{
// See if any previous data source negates this
PRBool hasNegation = PR_FALSE;
for (i = mNext - 1; i >= 0; --i)
{
nsIRDFDataSource* datasource =
mCompositeDataSource->mDataSources[i];
rv = HasNegation(datasource, mResult, &hasNegation);
if (NS_FAILED(rv)) return rv;
if (hasNegation)
break;
}
// if so, we've gotta keep looking
if (hasNegation)
{
NS_RELEASE(mResult);
continue;
}
}
if (mCoalesceDuplicateArcs)
{
// Now see if we've returned it once already.
// XXX N.B. performance here...may want to hash if things get large?
PRBool alreadyReturned = PR_FALSE;
for (i = mAlreadyReturned.Length() - 1; i >= 0; --i)
{
if (mAlreadyReturned[i] == mResult)
{
alreadyReturned = PR_TRUE;
break;
}
}
if (alreadyReturned)
{
NS_RELEASE(mResult);
continue;
}
}
// If we get here, then we've really found one. It'll
// remain cached in mResult until GetNext() sucks it out.
*aResult = PR_TRUE;
// Remember that we returned it, so we don't return duplicates.
// XXX I wonder if we should make unique-checking be
// optional. This could get to be pretty expensive (this
// implementation turns iteration into O(n^2)).
if (mCoalesceDuplicateArcs)
{
mAlreadyReturned.AppendElement(mResult);
}
return NS_OK;
} while (1);
}
// if we get here, there aren't any elements left.
*aResult = PR_FALSE;
return NS_OK;
}
NS_IMETHODIMP
CompositeEnumeratorImpl::GetNext(nsISupports** aResult)
{
nsresult rv;
PRBool hasMore;
rv = HasMoreElements(&hasMore);
if (NS_FAILED(rv)) return rv;
if (! hasMore)
return NS_ERROR_UNEXPECTED;
// Don't AddRef: we "transfer" ownership to the caller
*aResult = mResult;
mResult = nsnull;
return NS_OK;
}
//----------------------------------------------------------------------
//
// CompositeArcsInOutEnumeratorImpl
//
//
class CompositeArcsInOutEnumeratorImpl : public CompositeEnumeratorImpl
{
public:
enum Type { eArcsIn, eArcsOut };
static CompositeArcsInOutEnumeratorImpl*
Create(nsFixedSizeAllocator& aAllocator,
CompositeDataSourceImpl* aCompositeDataSource,
nsIRDFNode* aNode,
Type aType,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs) {
void* place = aAllocator.Alloc(sizeof(CompositeArcsInOutEnumeratorImpl));
return place
? ::new (place) CompositeArcsInOutEnumeratorImpl(aCompositeDataSource,
aNode, aType,
aAllowNegativeAssertions,
aCoalesceDuplicateArcs)
: nsnull; }
virtual ~CompositeArcsInOutEnumeratorImpl();
virtual nsresult
GetEnumerator(nsIRDFDataSource* aDataSource, nsISimpleEnumerator** aResult);
virtual nsresult
HasNegation(nsIRDFDataSource* aDataSource, nsIRDFNode* aNode, PRBool* aResult);
virtual void Destroy();
protected:
CompositeArcsInOutEnumeratorImpl(CompositeDataSourceImpl* aCompositeDataSource,
nsIRDFNode* aNode,
Type aType,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs);
private:
nsIRDFNode* mNode;
Type mType;
PRBool mAllowNegativeAssertions;
PRBool mCoalesceDuplicateArcs;
// Hide so that only Create() and Destroy() can be used to
// allocate and deallocate from the heap
static void* operator new(size_t) CPP_THROW_NEW { return 0; }
static void operator delete(void*, size_t) {}
};
CompositeArcsInOutEnumeratorImpl::CompositeArcsInOutEnumeratorImpl(
CompositeDataSourceImpl* aCompositeDataSource,
nsIRDFNode* aNode,
Type aType,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs)
: CompositeEnumeratorImpl(aCompositeDataSource, aAllowNegativeAssertions, aCoalesceDuplicateArcs),
mNode(aNode),
mType(aType),
mAllowNegativeAssertions(aAllowNegativeAssertions),
mCoalesceDuplicateArcs(aCoalesceDuplicateArcs)
{
NS_ADDREF(mNode);
}
CompositeArcsInOutEnumeratorImpl::~CompositeArcsInOutEnumeratorImpl()
{
NS_RELEASE(mNode);
}
nsresult
CompositeArcsInOutEnumeratorImpl::GetEnumerator(
nsIRDFDataSource* aDataSource,
nsISimpleEnumerator** aResult)
{
if (mType == eArcsIn) {
return aDataSource->ArcLabelsIn(mNode, aResult);
}
else {
nsCOMPtr<nsIRDFResource> resource( do_QueryInterface(mNode) );
return aDataSource->ArcLabelsOut(resource, aResult);
}
}
nsresult
CompositeArcsInOutEnumeratorImpl::HasNegation(
nsIRDFDataSource* aDataSource,
nsIRDFNode* aNode,
PRBool* aResult)
{
*aResult = PR_FALSE;
return NS_OK;
}
void
CompositeArcsInOutEnumeratorImpl::Destroy()
{
// Keep the datasource alive for the duration of the stack
// frame so its allocator stays valid.
nsCOMPtr<nsIRDFCompositeDataSource> kungFuDeathGrip = mCompositeDataSource;
nsFixedSizeAllocator& pool = mCompositeDataSource->mAllocator;
this->~CompositeArcsInOutEnumeratorImpl();
pool.Free(this, sizeof(*this));
}
//----------------------------------------------------------------------
//
// CompositeAssertionEnumeratorImpl
//
class CompositeAssertionEnumeratorImpl : public CompositeEnumeratorImpl
{
public:
static CompositeAssertionEnumeratorImpl*
Create(nsFixedSizeAllocator& aAllocator,
CompositeDataSourceImpl* aCompositeDataSource,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
PRBool aTruthValue,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs) {
void* place = aAllocator.Alloc(sizeof(CompositeAssertionEnumeratorImpl));
return place
? ::new (place) CompositeAssertionEnumeratorImpl(aCompositeDataSource,
aSource, aProperty, aTarget,
aTruthValue,
aAllowNegativeAssertions,
aCoalesceDuplicateArcs)
: nsnull; }
virtual nsresult
GetEnumerator(nsIRDFDataSource* aDataSource, nsISimpleEnumerator** aResult);
virtual nsresult
HasNegation(nsIRDFDataSource* aDataSource, nsIRDFNode* aNode, PRBool* aResult);
virtual void Destroy();
protected:
CompositeAssertionEnumeratorImpl(CompositeDataSourceImpl* aCompositeDataSource,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
PRBool aTruthValue,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs);
virtual ~CompositeAssertionEnumeratorImpl();
private:
nsIRDFResource* mSource;
nsIRDFResource* mProperty;
nsIRDFNode* mTarget;
PRBool mTruthValue;
PRBool mAllowNegativeAssertions;
PRBool mCoalesceDuplicateArcs;
// Hide so that only Create() and Destroy() can be used to
// allocate and deallocate from the heap
static void* operator new(size_t) CPP_THROW_NEW { return 0; }
static void operator delete(void*, size_t) {}
};
CompositeAssertionEnumeratorImpl::CompositeAssertionEnumeratorImpl(
CompositeDataSourceImpl* aCompositeDataSource,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
PRBool aTruthValue,
PRBool aAllowNegativeAssertions,
PRBool aCoalesceDuplicateArcs)
: CompositeEnumeratorImpl(aCompositeDataSource, aAllowNegativeAssertions, aCoalesceDuplicateArcs),
mSource(aSource),
mProperty(aProperty),
mTarget(aTarget),
mTruthValue(aTruthValue),
mAllowNegativeAssertions(aAllowNegativeAssertions),
mCoalesceDuplicateArcs(aCoalesceDuplicateArcs)
{
NS_IF_ADDREF(mSource);
NS_ADDREF(mProperty); // always must be specified
NS_IF_ADDREF(mTarget);
}
CompositeAssertionEnumeratorImpl::~CompositeAssertionEnumeratorImpl()
{
NS_IF_RELEASE(mSource);
NS_RELEASE(mProperty);
NS_IF_RELEASE(mTarget);
}
nsresult
CompositeAssertionEnumeratorImpl::GetEnumerator(
nsIRDFDataSource* aDataSource,
nsISimpleEnumerator** aResult)
{
if (mSource) {
return aDataSource->GetTargets(mSource, mProperty, mTruthValue, aResult);
}
else {
return aDataSource->GetSources(mProperty, mTarget, mTruthValue, aResult);
}
}
nsresult
CompositeAssertionEnumeratorImpl::HasNegation(
nsIRDFDataSource* aDataSource,
nsIRDFNode* aNode,
PRBool* aResult)
{
if (mSource) {
return aDataSource->HasAssertion(mSource, mProperty, aNode, !mTruthValue, aResult);
}
else {
nsCOMPtr<nsIRDFResource> source( do_QueryInterface(aNode) );
return aDataSource->HasAssertion(source, mProperty, mTarget, !mTruthValue, aResult);
}
}
void
CompositeAssertionEnumeratorImpl::Destroy()
{
// Keep the datasource alive for the duration of the stack
// frame so its allocator stays valid.
nsCOMPtr<nsIRDFCompositeDataSource> kungFuDeathGrip = mCompositeDataSource;
nsFixedSizeAllocator& pool = mCompositeDataSource->mAllocator;
this->~CompositeAssertionEnumeratorImpl();
pool.Free(this, sizeof(*this));
}
////////////////////////////////////////////////////////////////////////
nsresult
NS_NewRDFCompositeDataSource(nsIRDFCompositeDataSource** result)
{
CompositeDataSourceImpl* db = new CompositeDataSourceImpl();
if (! db)
return NS_ERROR_OUT_OF_MEMORY;
*result = db;
NS_ADDREF(*result);
return NS_OK;
}
CompositeDataSourceImpl::CompositeDataSourceImpl(void)
: mAllowNegativeAssertions(PR_TRUE),
mCoalesceDuplicateArcs(PR_TRUE),
mUpdateBatchNest(0)
{
static const size_t kBucketSizes[] = {
sizeof(CompositeAssertionEnumeratorImpl),
sizeof(CompositeArcsInOutEnumeratorImpl) };
static const PRInt32 kNumBuckets = sizeof(kBucketSizes) / sizeof(size_t);
// Per news://news.mozilla.org/39BEC105.5090206%40netscape.com
static const PRInt32 kInitialSize = 256;
mAllocator.Init("nsCompositeDataSource", kBucketSizes, kNumBuckets, kInitialSize);
#ifdef PR_LOGGING
if (nsRDFLog == nsnull)
nsRDFLog = PR_NewLogModule("RDF");
#endif
}
//----------------------------------------------------------------------
//
// nsISupports interface
//
NS_IMPL_CYCLE_COLLECTION_CLASS(CompositeDataSourceImpl)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CompositeDataSourceImpl)
PRUint32 i, count = tmp->mDataSources.Count();
for (i = count; i > 0; --i) {
tmp->mDataSources[i - 1]->RemoveObserver(tmp);
tmp->mDataSources.RemoveObjectAt(i - 1);
}
NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMARRAY(mObservers);
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CompositeDataSourceImpl)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMARRAY(mObservers)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMARRAY(mDataSources)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(CompositeDataSourceImpl)
NS_IMPL_CYCLE_COLLECTING_RELEASE(CompositeDataSourceImpl)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CompositeDataSourceImpl)
NS_INTERFACE_MAP_ENTRY(nsIRDFCompositeDataSource)
NS_INTERFACE_MAP_ENTRY(nsIRDFDataSource)
NS_INTERFACE_MAP_ENTRY(nsIRDFObserver)
NS_INTERFACE_MAP_ENTRY(nsIRDFCompositeDataSource)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIRDFCompositeDataSource)
NS_INTERFACE_MAP_END
//----------------------------------------------------------------------
//
// nsIRDFDataSource interface
//
NS_IMETHODIMP
CompositeDataSourceImpl::GetURI(char* *uri)
{
*uri = nsnull;
return NS_OK;
}
NS_IMETHODIMP
CompositeDataSourceImpl::GetSource(nsIRDFResource* property,
nsIRDFNode* target,
PRBool tv,
nsIRDFResource** source)
{
if (!mAllowNegativeAssertions && !tv)
return(NS_RDF_NO_VALUE);
PRInt32 count = mDataSources.Count();
for (PRInt32 i = 0; i < count; ++i) {
nsresult rv;
rv = mDataSources[i]->GetSource(property, target, tv, source);
if (NS_FAILED(rv)) return rv;
if (rv == NS_RDF_NO_VALUE)
continue;
if (!mAllowNegativeAssertions) return(NS_OK);
// okay, found it. make sure we don't have the opposite
// asserted in a more local data source
if (!HasAssertionN(count-1, *source, property, target, !tv))
return NS_OK;
NS_RELEASE(*source);
return NS_RDF_NO_VALUE;
}
return NS_RDF_NO_VALUE;
}
NS_IMETHODIMP
CompositeDataSourceImpl::GetSources(nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
PRBool aTruthValue,
nsISimpleEnumerator** aResult)
{
NS_PRECONDITION(aProperty != nsnull, "null ptr");
if (! aProperty)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aTarget != nsnull, "null ptr");
if (! aTarget)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aResult != nsnull, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
if (! mAllowNegativeAssertions && ! aTruthValue)
return(NS_RDF_NO_VALUE);
*aResult = CompositeAssertionEnumeratorImpl::Create(mAllocator,
this, nsnull, aProperty,
aTarget, aTruthValue,
mAllowNegativeAssertions,
mCoalesceDuplicateArcs);
if (! *aResult)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(*aResult);
return NS_OK;
}
NS_IMETHODIMP
CompositeDataSourceImpl::GetTarget(nsIRDFResource* aSource,
nsIRDFResource* aProperty,
PRBool aTruthValue,
nsIRDFNode** aResult)
{
NS_PRECONDITION(aSource != nsnull, "null ptr");
if (! aSource)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aProperty != nsnull, "null ptr");
if (! aProperty)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aResult != nsnull, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
if (! mAllowNegativeAssertions && ! aTruthValue)
return(NS_RDF_NO_VALUE);
PRInt32 count = mDataSources.Count();
for (PRInt32 i = 0; i < count; ++i) {
nsresult rv;
rv = mDataSources[i]->GetTarget(aSource, aProperty, aTruthValue,
aResult);
if (NS_FAILED(rv))
return rv;
if (rv == NS_OK) {
// okay, found it. make sure we don't have the opposite
// asserted in an earlier data source
if (mAllowNegativeAssertions) {
if (HasAssertionN(count-1, aSource, aProperty, *aResult, !aTruthValue)) {
// whoops, it's been negated.
NS_RELEASE(*aResult);
return NS_RDF_NO_VALUE;
}
}
return NS_OK;
}
}
// Otherwise, we couldn't find it at all.
return NS_RDF_NO_VALUE;
}
PRBool
CompositeDataSourceImpl::HasAssertionN(int n,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
PRBool aTruthValue)
{
nsresult rv;
for (PRInt32 m = 0; m < n; ++m) {
PRBool result;
rv = mDataSources[m]->HasAssertion(aSource, aProperty, aTarget,
aTruthValue, &result);
if (NS_FAILED(rv))
return PR_FALSE;
// found it!
if (result)
return PR_TRUE;
}
return PR_FALSE;
}
NS_IMETHODIMP
CompositeDataSourceImpl::GetTargets(nsIRDFResource* aSource,
nsIRDFResource* aProperty,
PRBool aTruthValue,
nsISimpleEnumerator** aResult)
{
NS_PRECONDITION(aSource != nsnull, "null ptr");
if (! aSource)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aProperty != nsnull, "null ptr");
if (! aProperty)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aResult != nsnull, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
if (! mAllowNegativeAssertions && ! aTruthValue)
return(NS_RDF_NO_VALUE);
*aResult =
CompositeAssertionEnumeratorImpl::Create(mAllocator, this,
aSource, aProperty, nsnull,
aTruthValue,
mAllowNegativeAssertions,
mCoalesceDuplicateArcs);
if (! *aResult)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(*aResult);
return NS_OK;
}
NS_IMETHODIMP
CompositeDataSourceImpl::Assert(nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
PRBool aTruthValue)
{
NS_PRECONDITION(aSource != nsnull, "null ptr");
if (! aSource)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aProperty != nsnull, "null ptr");
if (! aProperty)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aTarget != nsnull, "null ptr");
if (! aTarget)
return NS_ERROR_NULL_POINTER;
if (! mAllowNegativeAssertions && ! aTruthValue)
return(NS_RDF_ASSERTION_REJECTED);
nsresult rv;
// XXX Need to add back the stuff for unblocking ...
// We iterate backwards from the last data source which was added
// ("the most remote") to the first ("the most local"), trying to
// apply the assertion in each.
for (PRInt32 i = mDataSources.Count() - 1; i >= 0; --i) {
rv = mDataSources[i]->Assert(aSource, aProperty, aTarget, aTruthValue);
if (NS_RDF_ASSERTION_ACCEPTED == rv)
return rv;
if (NS_FAILED(rv))
return rv;
}
// nobody wanted to accept it
return NS_RDF_ASSERTION_REJECTED;
}
NS_IMETHODIMP
CompositeDataSourceImpl::Unassert(nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget)
{
NS_PRECONDITION(aSource != nsnull, "null ptr");
if (! aSource)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aProperty != nsnull, "null ptr");
if (! aProperty)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aTarget != nsnull, "null ptr");
if (! aTarget)
return NS_ERROR_NULL_POINTER;
nsresult rv;
// Iterate through each of the datasources, starting with "the
// most local" and moving to "the most remote". If _any_ of the
// datasources have the assertion, attempt to unassert it.
PRBool unasserted = PR_TRUE;
PRInt32 i;
PRInt32 count = mDataSources.Count();
for (i = 0; i < count; ++i) {
nsIRDFDataSource* ds = mDataSources[i];
PRBool hasAssertion;
rv = ds->HasAssertion(aSource, aProperty, aTarget, PR_TRUE, &hasAssertion);
if (NS_FAILED(rv)) return rv;
if (hasAssertion) {
rv = ds->Unassert(aSource, aProperty, aTarget);
if (NS_FAILED(rv)) return rv;
if (rv != NS_RDF_ASSERTION_ACCEPTED) {
unasserted = PR_FALSE;
break;
}
}
}
// Either none of the datasources had it, or they were all willing
// to let it be unasserted.
if (unasserted)
return NS_RDF_ASSERTION_ACCEPTED;
// If we get here, one of the datasources already had the
// assertion, and was adamant about not letting us remove
// it. Iterate from the "most local" to the "most remote"
// attempting to assert the negation...
for (i = 0; i < count; ++i) {
rv = mDataSources[i]->Assert(aSource, aProperty, aTarget, PR_FALSE);
if (NS_FAILED(rv)) return rv;
// Did it take?
if (rv == NS_RDF_ASSERTION_ACCEPTED)
return rv;
}
// Couln't get anyone to accept the negation, either.
return NS_RDF_ASSERTION_REJECTED;
}
NS_IMETHODIMP
CompositeDataSourceImpl::Change(nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aOldTarget,
nsIRDFNode* aNewTarget)
{
NS_PRECONDITION(aSource != nsnull, "null ptr");
if (! aSource)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aProperty != nsnull, "null ptr");
if (! aProperty)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aOldTarget != nsnull, "null ptr");
if (! aOldTarget)
return NS_ERROR_NULL_POINTER;
NS_PRECONDITION(aNewTarget != nsnull, "null ptr");
if (! aNewTarget)
return NS_ERROR_NULL_POINTER;
nsresult rv;
// XXX So we're assuming that a datasource _must_ accept the
// atomic change; i.e., we can't split it up across two
// datasources. That sucks.
// We iterate backwards from the last data source which was added
// ("the most remote") to the first ("the most local"), trying to
// apply the change in each.
for (PRInt32 i = mDataSources.Count() - 1; i >= 0; --i) {
rv = mDataSources[i]->Change(aSource, aProperty, aOldTarget, aNewTarget);
if (NS_RDF_ASSERTION_ACCEPTED == rv)
return rv;
if (NS_FAILED(rv))
return rv;
}
// nobody wanted to accept it
return NS_RDF_ASSERTION_REJECTED;