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nsInMemoryDataSource.cpp
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nsInMemoryDataSource.cpp
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
*
* This Original Code has been modified by IBM Corporation.
* Modifications made by IBM described herein are
* Copyright (c) International Business Machines
* Corporation, 2000
*
* Modifications to Mozilla code or documentation
* identified per MPL Section 3.3
*
* Date Modified by Description of modification
* 03/27/2000 IBM Corp. Added PR_CALLBACK for Optlink
* use in OS2
*/
/*
Implementation for an in-memory RDF data store.
TO DO
1) Instrument this code to gather space and time performance
characteristics.
2) Optimize lookups for datasources which have a small number
of properties + fanning out to a large number of targets.
3) Complete implementation of thread-safety; specifically, make
assertions be reference counted objects (so that a cursor can
still refer to an assertion that gets removed from the graph).
*/
#include "nsAgg.h"
#include "nsCOMPtr.h"
#include "nscore.h"
#include "nsIOutputStream.h"
#include "nsIRDFDataSource.h"
#include "nsIRDFLiteral.h"
#include "nsIRDFNode.h"
#include "nsIRDFObserver.h"
#include "nsIRDFInMemoryDataSource.h"
#include "nsIRDFPropagatableDataSource.h"
#include "nsIRDFPurgeableDataSource.h"
#include "nsIRDFService.h"
#include "nsIServiceManager.h"
#include "nsISupportsArray.h"
#include "nsCOMArray.h"
#include "nsEnumeratorUtils.h"
#include "nsTArray.h"
#include "nsCRT.h"
#include "nsRDFCID.h"
#include "nsRDFBaseDataSources.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "nsXPIDLString.h"
#include "nsFixedSizeAllocator.h"
#include "rdfutil.h"
#include "pldhash.h"
#include "plstr.h"
#include "prlog.h"
#include "rdf.h"
#include "rdfIDataSource.h"
#include "rdfITripleVisitor.h"
#ifdef PR_LOGGING
static PRLogModuleInfo* gLog = nsnull;
#endif
// This struct is used as the slot value in the forward and reverse
// arcs hash tables.
//
// Assertion objects are reference counted, because each Assertion's
// ownership is shared between the datasource and any enumerators that
// are currently iterating over the datasource.
//
class Assertion
{
public:
static Assertion*
Create(nsFixedSizeAllocator& aAllocator,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue) {
void* place = aAllocator.Alloc(sizeof(Assertion));
return place
? ::new (place) Assertion(aSource, aProperty, aTarget, aTruthValue)
: nsnull; }
static Assertion*
Create(nsFixedSizeAllocator& aAllocator, nsIRDFResource* aSource) {
void* place = aAllocator.Alloc(sizeof(Assertion));
return place
? ::new (place) Assertion(aSource)
: nsnull; }
static void
Destroy(nsFixedSizeAllocator& aAllocator, Assertion* aAssertion) {
if (aAssertion->mHashEntry && aAssertion->u.hash.mPropertyHash) {
PL_DHashTableEnumerate(aAssertion->u.hash.mPropertyHash,
DeletePropertyHashEntry, &aAllocator);
PL_DHashTableDestroy(aAssertion->u.hash.mPropertyHash);
aAssertion->u.hash.mPropertyHash = nsnull;
}
aAssertion->~Assertion();
aAllocator.Free(aAssertion, sizeof(*aAssertion)); }
static PLDHashOperator
DeletePropertyHashEntry(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg);
Assertion(nsIRDFResource* aSource, // normal assertion
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue);
Assertion(nsIRDFResource* aSource); // PLDHashTable assertion variant
~Assertion();
void AddRef() {
if (mRefCnt == PR_UINT16_MAX) {
NS_WARNING("refcount overflow, leaking Assertion");
return;
}
++mRefCnt;
}
void Release(nsFixedSizeAllocator& aAllocator) {
if (mRefCnt == PR_UINT16_MAX) {
NS_WARNING("refcount overflow, leaking Assertion");
return;
}
if (--mRefCnt == 0)
Destroy(aAllocator, this);
}
// For nsIRDFPurgeableDataSource
inline void Mark() { u.as.mMarked = true; }
inline bool IsMarked() { return u.as.mMarked; }
inline void Unmark() { u.as.mMarked = false; }
// public for now, because I'm too lazy to go thru and clean this up.
// These are shared between hash/as (see the union below)
nsIRDFResource* mSource;
Assertion* mNext;
union
{
struct hash
{
PLDHashTable* mPropertyHash;
} hash;
struct as
{
nsIRDFResource* mProperty;
nsIRDFNode* mTarget;
Assertion* mInvNext;
// make sure bool are final elements
bool mTruthValue;
bool mMarked;
} as;
} u;
// also shared between hash/as (see the union above)
// but placed after union definition to ensure that
// all 32-bit entries are long aligned
PRUint16 mRefCnt;
bool mHashEntry;
private:
// 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) {}
};
struct Entry {
PLDHashEntryHdr mHdr;
nsIRDFNode* mNode;
Assertion* mAssertions;
};
Assertion::Assertion(nsIRDFResource* aSource)
: mSource(aSource),
mNext(nsnull),
mRefCnt(0),
mHashEntry(true)
{
MOZ_COUNT_CTOR(RDF_Assertion);
NS_ADDREF(mSource);
u.hash.mPropertyHash = PL_NewDHashTable(PL_DHashGetStubOps(),
nsnull, sizeof(Entry), PL_DHASH_MIN_SIZE);
}
Assertion::Assertion(nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue)
: mSource(aSource),
mNext(nsnull),
mRefCnt(0),
mHashEntry(false)
{
MOZ_COUNT_CTOR(RDF_Assertion);
u.as.mProperty = aProperty;
u.as.mTarget = aTarget;
NS_ADDREF(mSource);
NS_ADDREF(u.as.mProperty);
NS_ADDREF(u.as.mTarget);
u.as.mInvNext = nsnull;
u.as.mTruthValue = aTruthValue;
u.as.mMarked = false;
}
Assertion::~Assertion()
{
MOZ_COUNT_DTOR(RDF_Assertion);
#ifdef DEBUG_REFS
--gInstanceCount;
fprintf(stdout, "%d - RDF: Assertion\n", gInstanceCount);
#endif
NS_RELEASE(mSource);
if (!mHashEntry)
{
NS_RELEASE(u.as.mProperty);
NS_RELEASE(u.as.mTarget);
}
}
PLDHashOperator
Assertion::DeletePropertyHashEntry(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg)
{
Entry* entry = reinterpret_cast<Entry*>(aHdr);
nsFixedSizeAllocator* allocator = static_cast<nsFixedSizeAllocator*>(aArg);
Assertion* as = entry->mAssertions;
while (as) {
Assertion* doomed = as;
as = as->mNext;
// Unlink, and release the datasource's reference.
doomed->mNext = doomed->u.as.mInvNext = nsnull;
doomed->Release(*allocator);
}
return PL_DHASH_NEXT;
}
////////////////////////////////////////////////////////////////////////
// InMemoryDataSource
class InMemoryArcsEnumeratorImpl;
class InMemoryAssertionEnumeratorImpl;
class InMemoryResourceEnumeratorImpl;
class InMemoryDataSource : public nsIRDFDataSource,
public nsIRDFInMemoryDataSource,
public nsIRDFPropagatableDataSource,
public nsIRDFPurgeableDataSource,
public rdfIDataSource
{
protected:
nsFixedSizeAllocator mAllocator;
// These hash tables are keyed on pointers to nsIRDFResource
// objects (the nsIRDFService ensures that there is only ever one
// nsIRDFResource object per unique URI). The value of an entry is
// an Assertion struct, which is a linked list of (subject
// predicate object) triples.
PLDHashTable mForwardArcs;
PLDHashTable mReverseArcs;
nsCOMArray<nsIRDFObserver> mObservers;
PRUint32 mNumObservers;
// VisitFoo needs to block writes, [Un]Assert only allowed
// during mReadCount == 0
PRUint32 mReadCount;
static PLDHashOperator
DeleteForwardArcsEntry(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg);
static PLDHashOperator
ResourceEnumerator(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg);
friend class InMemoryArcsEnumeratorImpl;
friend class InMemoryAssertionEnumeratorImpl;
friend class InMemoryResourceEnumeratorImpl; // b/c it needs to enumerate mForwardArcs
// Thread-safe writer implementation methods.
nsresult
LockedAssert(nsIRDFResource* source,
nsIRDFResource* property,
nsIRDFNode* target,
bool tv);
nsresult
LockedUnassert(nsIRDFResource* source,
nsIRDFResource* property,
nsIRDFNode* target);
InMemoryDataSource(nsISupports* aOuter);
virtual ~InMemoryDataSource();
nsresult Init();
friend nsresult
NS_NewRDFInMemoryDataSource(nsISupports* aOuter, const nsIID& aIID, void** aResult);
public:
NS_DECL_CYCLE_COLLECTING_AGGREGATED
NS_DECL_AGGREGATED_CYCLE_COLLECTION_CLASS(InMemoryDataSource)
// nsIRDFDataSource methods
NS_DECL_NSIRDFDATASOURCE
// nsIRDFInMemoryDataSource methods
NS_DECL_NSIRDFINMEMORYDATASOURCE
// nsIRDFPropagatableDataSource methods
NS_DECL_NSIRDFPROPAGATABLEDATASOURCE
// nsIRDFPurgeableDataSource methods
NS_DECL_NSIRDFPURGEABLEDATASOURCE
// rdfIDataSource methods
NS_DECL_RDFIDATASOURCE
protected:
static PLDHashOperator
SweepForwardArcsEntries(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg);
public:
// Implementation methods
Assertion*
GetForwardArcs(nsIRDFResource* u) {
PLDHashEntryHdr* hdr = PL_DHashTableOperate(&mForwardArcs, u, PL_DHASH_LOOKUP);
return PL_DHASH_ENTRY_IS_BUSY(hdr)
? reinterpret_cast<Entry*>(hdr)->mAssertions
: nsnull; }
Assertion*
GetReverseArcs(nsIRDFNode* v) {
PLDHashEntryHdr* hdr = PL_DHashTableOperate(&mReverseArcs, v, PL_DHASH_LOOKUP);
return PL_DHASH_ENTRY_IS_BUSY(hdr)
? reinterpret_cast<Entry*>(hdr)->mAssertions
: nsnull; }
void
SetForwardArcs(nsIRDFResource* u, Assertion* as) {
PLDHashEntryHdr* hdr = PL_DHashTableOperate(&mForwardArcs, u,
as ? PL_DHASH_ADD : PL_DHASH_REMOVE);
if (as && hdr) {
Entry* entry = reinterpret_cast<Entry*>(hdr);
entry->mNode = u;
entry->mAssertions = as;
} }
void
SetReverseArcs(nsIRDFNode* v, Assertion* as) {
PLDHashEntryHdr* hdr = PL_DHashTableOperate(&mReverseArcs, v,
as ? PL_DHASH_ADD : PL_DHASH_REMOVE);
if (as && hdr) {
Entry* entry = reinterpret_cast<Entry*>(hdr);
entry->mNode = v;
entry->mAssertions = as;
} }
#ifdef PR_LOGGING
void
LogOperation(const char* aOperation,
nsIRDFResource* asource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue = true);
#endif
bool mPropagateChanges;
};
//----------------------------------------------------------------------
//
// InMemoryAssertionEnumeratorImpl
//
/**
* InMemoryAssertionEnumeratorImpl
*/
class InMemoryAssertionEnumeratorImpl : public nsISimpleEnumerator
{
private:
InMemoryDataSource* mDataSource;
nsIRDFResource* mSource;
nsIRDFResource* mProperty;
nsIRDFNode* mTarget;
nsIRDFNode* mValue;
bool mTruthValue;
Assertion* mNextAssertion;
nsCOMPtr<nsISupportsArray> mHashArcs;
// 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) {}
InMemoryAssertionEnumeratorImpl(InMemoryDataSource* aDataSource,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue);
virtual ~InMemoryAssertionEnumeratorImpl();
public:
static InMemoryAssertionEnumeratorImpl*
Create(InMemoryDataSource* aDataSource,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue) {
void* place = aDataSource->mAllocator.Alloc(sizeof(InMemoryAssertionEnumeratorImpl));
return place
? ::new (place) InMemoryAssertionEnumeratorImpl(aDataSource,
aSource, aProperty, aTarget,
aTruthValue)
: nsnull; }
static void
Destroy(InMemoryAssertionEnumeratorImpl* aEnumerator) {
// Keep the datasource alive for the duration of the stack
// frame so its allocator stays valid.
nsCOMPtr<nsIRDFDataSource> kungFuDeathGrip = aEnumerator->mDataSource;
// Grab the pool from the datasource; since we keep the
// datasource alive, this has to be safe.
nsFixedSizeAllocator& pool = aEnumerator->mDataSource->mAllocator;
aEnumerator->~InMemoryAssertionEnumeratorImpl();
pool.Free(aEnumerator, sizeof(*aEnumerator)); }
// nsISupports interface
NS_DECL_ISUPPORTS
// nsISimpleEnumerator interface
NS_DECL_NSISIMPLEENUMERATOR
};
////////////////////////////////////////////////////////////////////////
InMemoryAssertionEnumeratorImpl::InMemoryAssertionEnumeratorImpl(
InMemoryDataSource* aDataSource,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue)
: mDataSource(aDataSource),
mSource(aSource),
mProperty(aProperty),
mTarget(aTarget),
mValue(nsnull),
mTruthValue(aTruthValue),
mNextAssertion(nsnull)
{
NS_ADDREF(mDataSource);
NS_IF_ADDREF(mSource);
NS_ADDREF(mProperty);
NS_IF_ADDREF(mTarget);
if (mSource) {
mNextAssertion = mDataSource->GetForwardArcs(mSource);
if (mNextAssertion && mNextAssertion->mHashEntry) {
// its our magical HASH_ENTRY forward hash for assertions
PLDHashEntryHdr* hdr = PL_DHashTableOperate(mNextAssertion->u.hash.mPropertyHash,
aProperty, PL_DHASH_LOOKUP);
mNextAssertion = PL_DHASH_ENTRY_IS_BUSY(hdr)
? reinterpret_cast<Entry*>(hdr)->mAssertions
: nsnull;
}
}
else {
mNextAssertion = mDataSource->GetReverseArcs(mTarget);
}
// Add an owning reference from the enumerator
if (mNextAssertion)
mNextAssertion->AddRef();
}
InMemoryAssertionEnumeratorImpl::~InMemoryAssertionEnumeratorImpl()
{
#ifdef DEBUG_REFS
--gInstanceCount;
fprintf(stdout, "%d - RDF: InMemoryAssertionEnumeratorImpl\n", gInstanceCount);
#endif
if (mNextAssertion)
mNextAssertion->Release(mDataSource->mAllocator);
NS_IF_RELEASE(mDataSource);
NS_IF_RELEASE(mSource);
NS_IF_RELEASE(mProperty);
NS_IF_RELEASE(mTarget);
NS_IF_RELEASE(mValue);
}
NS_IMPL_ADDREF(InMemoryAssertionEnumeratorImpl)
NS_IMPL_RELEASE_WITH_DESTROY(InMemoryAssertionEnumeratorImpl, Destroy(this))
NS_IMPL_QUERY_INTERFACE1(InMemoryAssertionEnumeratorImpl, nsISimpleEnumerator)
NS_IMETHODIMP
InMemoryAssertionEnumeratorImpl::HasMoreElements(bool* aResult)
{
if (mValue) {
*aResult = true;
return NS_OK;
}
while (mNextAssertion) {
bool foundIt = false;
if ((mProperty == mNextAssertion->u.as.mProperty) &&
(mTruthValue == mNextAssertion->u.as.mTruthValue)) {
if (mSource) {
mValue = mNextAssertion->u.as.mTarget;
NS_ADDREF(mValue);
}
else {
mValue = mNextAssertion->mSource;
NS_ADDREF(mValue);
}
foundIt = true;
}
// Remember the last assertion we were holding on to
Assertion* as = mNextAssertion;
// iterate
mNextAssertion = (mSource) ? mNextAssertion->mNext : mNextAssertion->u.as.mInvNext;
// grab an owning reference from the enumerator to the next assertion
if (mNextAssertion)
mNextAssertion->AddRef();
// ...and release the reference from the enumerator to the old one.
as->Release(mDataSource->mAllocator);
if (foundIt) {
*aResult = true;
return NS_OK;
}
}
*aResult = false;
return NS_OK;
}
NS_IMETHODIMP
InMemoryAssertionEnumeratorImpl::GetNext(nsISupports** aResult)
{
nsresult rv;
bool 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 = mValue;
mValue = nsnull;
return NS_OK;
}
////////////////////////////////////////////////////////////////////////
//
/**
* This class is a little bit bizarre in that it implements both the
* <tt>nsIRDFArcsOutCursor</tt> and <tt>nsIRDFArcsInCursor</tt> interfaces.
* Because the structure of the in-memory graph is pretty flexible, it's
* fairly easy to parameterize this class. The only funky thing to watch
* out for is the multiple inheritance clashes.
*/
class InMemoryArcsEnumeratorImpl : public nsISimpleEnumerator
{
private:
// 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) {}
InMemoryDataSource* mDataSource;
nsIRDFResource* mSource;
nsIRDFNode* mTarget;
nsAutoTArray<nsCOMPtr<nsIRDFResource>, 8> mAlreadyReturned;
nsIRDFResource* mCurrent;
Assertion* mAssertion;
nsCOMPtr<nsISupportsArray> mHashArcs;
InMemoryArcsEnumeratorImpl(InMemoryDataSource* aDataSource,
nsIRDFResource* aSource,
nsIRDFNode* aTarget);
virtual ~InMemoryArcsEnumeratorImpl();
static PLDHashOperator
ArcEnumerator(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg);
public:
// nsISupports interface
NS_DECL_ISUPPORTS
// nsISimpleEnumerator interface
NS_DECL_NSISIMPLEENUMERATOR
static InMemoryArcsEnumeratorImpl*
Create(InMemoryDataSource* aDataSource,
nsIRDFResource* aSource,
nsIRDFNode* aTarget) {
void* place = aDataSource->mAllocator.Alloc(sizeof(InMemoryArcsEnumeratorImpl));
return place
? ::new (place) InMemoryArcsEnumeratorImpl(aDataSource, aSource, aTarget)
: nsnull; }
static void
Destroy(InMemoryArcsEnumeratorImpl* aEnumerator) {
// Keep the datasource alive for the duration of the stack
// frame so its allocator stays valid.
nsCOMPtr<nsIRDFDataSource> kungFuDeathGrip = aEnumerator->mDataSource;
// Grab the pool from the datasource; since we keep the
// datasource alive, this has to be safe.
nsFixedSizeAllocator& pool = aEnumerator->mDataSource->mAllocator;
aEnumerator->~InMemoryArcsEnumeratorImpl();
pool.Free(aEnumerator, sizeof(*aEnumerator)); }
};
PLDHashOperator
InMemoryArcsEnumeratorImpl::ArcEnumerator(PLDHashTable* aTable,
PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg)
{
Entry* entry = reinterpret_cast<Entry*>(aHdr);
nsISupportsArray* resources = static_cast<nsISupportsArray*>(aArg);
resources->AppendElement(entry->mNode);
return PL_DHASH_NEXT;
}
InMemoryArcsEnumeratorImpl::InMemoryArcsEnumeratorImpl(InMemoryDataSource* aDataSource,
nsIRDFResource* aSource,
nsIRDFNode* aTarget)
: mDataSource(aDataSource),
mSource(aSource),
mTarget(aTarget),
mCurrent(nsnull)
{
NS_ADDREF(mDataSource);
NS_IF_ADDREF(mSource);
NS_IF_ADDREF(mTarget);
if (mSource) {
// cast okay because it's a closed system
mAssertion = mDataSource->GetForwardArcs(mSource);
if (mAssertion && mAssertion->mHashEntry) {
// its our magical HASH_ENTRY forward hash for assertions
nsresult rv = NS_NewISupportsArray(getter_AddRefs(mHashArcs));
if (NS_SUCCEEDED(rv)) {
PL_DHashTableEnumerate(mAssertion->u.hash.mPropertyHash,
ArcEnumerator, mHashArcs.get());
}
mAssertion = nsnull;
}
}
else {
mAssertion = mDataSource->GetReverseArcs(mTarget);
}
}
InMemoryArcsEnumeratorImpl::~InMemoryArcsEnumeratorImpl()
{
#ifdef DEBUG_REFS
--gInstanceCount;
fprintf(stdout, "%d - RDF: InMemoryArcsEnumeratorImpl\n", gInstanceCount);
#endif
NS_RELEASE(mDataSource);
NS_IF_RELEASE(mSource);
NS_IF_RELEASE(mTarget);
NS_IF_RELEASE(mCurrent);
}
NS_IMPL_ADDREF(InMemoryArcsEnumeratorImpl)
NS_IMPL_RELEASE_WITH_DESTROY(InMemoryArcsEnumeratorImpl, Destroy(this))
NS_IMPL_QUERY_INTERFACE1(InMemoryArcsEnumeratorImpl, nsISimpleEnumerator)
NS_IMETHODIMP
InMemoryArcsEnumeratorImpl::HasMoreElements(bool* aResult)
{
NS_PRECONDITION(aResult != nsnull, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
if (mCurrent) {
*aResult = true;
return NS_OK;
}
if (mHashArcs) {
PRUint32 itemCount;
nsresult rv;
if (NS_FAILED(rv = mHashArcs->Count(&itemCount))) return(rv);
if (itemCount > 0) {
--itemCount;
mCurrent = static_cast<nsIRDFResource *>
(mHashArcs->ElementAt(itemCount));
mHashArcs->RemoveElementAt(itemCount);
*aResult = true;
return NS_OK;
}
}
else
while (mAssertion) {
nsIRDFResource* next = mAssertion->u.as.mProperty;
// "next" is the property arc we are tentatively going to return
// in a subsequent GetNext() call. It is important to do two
// things, however, before that can happen:
// 1) Make sure it's not an arc we've already returned.
// 2) Make sure that |mAssertion| is not left pointing to
// another assertion that has the same property as this one.
// The first is a practical concern; the second a defense against
// an obscure crash and other erratic behavior. To ensure the
// second condition, skip down the chain until we find the next
// assertion with a property that doesn't match the current one.
// (All these assertions would be skipped via mAlreadyReturned
// checks anyways; this is even a bit faster.)
do {
mAssertion = (mSource ? mAssertion->mNext :
mAssertion->u.as.mInvNext);
}
while (mAssertion && (next == mAssertion->u.as.mProperty));
bool alreadyReturned = false;
for (PRInt32 i = mAlreadyReturned.Length() - 1; i >= 0; --i) {
if (mAlreadyReturned[i] == next) {
alreadyReturned = true;
break;
}
}
if (! alreadyReturned) {
mCurrent = next;
NS_ADDREF(mCurrent);
*aResult = true;
return NS_OK;
}
}
*aResult = false;
return NS_OK;
}
NS_IMETHODIMP
InMemoryArcsEnumeratorImpl::GetNext(nsISupports** aResult)
{
nsresult rv;
bool hasMore;
rv = HasMoreElements(&hasMore);
if (NS_FAILED(rv)) return rv;
if (! hasMore)
return NS_ERROR_UNEXPECTED;
// Add this to the set of things we've already returned so that we
// can ensure uniqueness
mAlreadyReturned.AppendElement(mCurrent);
// Don't AddRef: we "transfer" ownership to the caller
*aResult = mCurrent;
mCurrent = nsnull;
return NS_OK;
}
////////////////////////////////////////////////////////////////////////
// InMemoryDataSource
nsresult
NS_NewRDFInMemoryDataSource(nsISupports* aOuter, const nsIID& aIID, void** aResult)
{
NS_PRECONDITION(aResult != nsnull, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
*aResult = nsnull;
if (aOuter && !aIID.Equals(NS_GET_IID(nsISupports))) {
NS_ERROR("aggregation requires nsISupports");
return NS_ERROR_ILLEGAL_VALUE;
}
InMemoryDataSource* datasource = new InMemoryDataSource(aOuter);
if (! datasource)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(datasource);
nsresult rv = datasource->Init();
if (NS_SUCCEEDED(rv)) {
datasource->fAggregated.AddRef();
rv = datasource->AggregatedQueryInterface(aIID, aResult); // This'll AddRef()
datasource->fAggregated.Release();
}
NS_RELEASE(datasource);
return rv;
}
InMemoryDataSource::InMemoryDataSource(nsISupports* aOuter)
: mNumObservers(0), mReadCount(0)
{
NS_INIT_AGGREGATED(aOuter);
static const size_t kBucketSizes[] = {
sizeof(Assertion),
sizeof(Entry),
sizeof(InMemoryArcsEnumeratorImpl),
sizeof(InMemoryAssertionEnumeratorImpl) };
static const PRInt32 kNumBuckets = sizeof(kBucketSizes) / sizeof(size_t);
// Per news://news.mozilla.org/39BEC105.5090206%40netscape.com
static const PRInt32 kInitialSize = 1024;
mAllocator.Init("nsInMemoryDataSource", kBucketSizes, kNumBuckets, kInitialSize);
mForwardArcs.ops = nsnull;
mReverseArcs.ops = nsnull;
mPropagateChanges = true;
}
nsresult
InMemoryDataSource::Init()
{
if (!PL_DHashTableInit(&mForwardArcs,
PL_DHashGetStubOps(),
nsnull,
sizeof(Entry),
PL_DHASH_MIN_SIZE)) {
mForwardArcs.ops = nsnull;
return NS_ERROR_OUT_OF_MEMORY;
}
if (!PL_DHashTableInit(&mReverseArcs,
PL_DHashGetStubOps(),
nsnull,
sizeof(Entry),
PL_DHASH_MIN_SIZE)) {
mReverseArcs.ops = nsnull;
return NS_ERROR_OUT_OF_MEMORY;
}
#ifdef PR_LOGGING
if (! gLog)
gLog = PR_NewLogModule("InMemoryDataSource");
#endif
return NS_OK;
}
InMemoryDataSource::~InMemoryDataSource()
{
#ifdef DEBUG_REFS
--gInstanceCount;
fprintf(stdout, "%d - RDF: InMemoryDataSource\n", gInstanceCount);
#endif
if (mForwardArcs.ops) {
// This'll release all of the Assertion objects that are
// associated with this data source. We only need to do this
// for the forward arcs, because the reverse arcs table
// indexes the exact same set of resources.
PL_DHashTableEnumerate(&mForwardArcs, DeleteForwardArcsEntry, &mAllocator);
PL_DHashTableFinish(&mForwardArcs);
}
if (mReverseArcs.ops)
PL_DHashTableFinish(&mReverseArcs);
PR_LOG(gLog, PR_LOG_NOTICE,
("InMemoryDataSource(%p): destroyed.", this));
}
PLDHashOperator
InMemoryDataSource::DeleteForwardArcsEntry(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
PRUint32 aNumber, void* aArg)
{
Entry* entry = reinterpret_cast<Entry*>(aHdr);
nsFixedSizeAllocator* allocator = static_cast<nsFixedSizeAllocator*>(aArg);
Assertion* as = entry->mAssertions;
while (as) {
Assertion* doomed = as;
as = as->mNext;
// Unlink, and release the datasource's reference.
doomed->mNext = doomed->u.as.mInvNext = nsnull;
doomed->Release(*allocator);
}
return PL_DHASH_NEXT;
}
////////////////////////////////////////////////////////////////////////
NS_IMPL_CYCLE_COLLECTION_CLASS(InMemoryDataSource)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(InMemoryDataSource)
NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMARRAY(mObservers)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_AGGREGATED(InMemoryDataSource)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMARRAY(mObservers)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTING_AGGREGATED(InMemoryDataSource)
NS_INTERFACE_MAP_BEGIN_AGGREGATED(InMemoryDataSource)
NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION_AGGREGATED(InMemoryDataSource)
NS_INTERFACE_MAP_ENTRY(nsIRDFDataSource)
NS_INTERFACE_MAP_ENTRY(nsIRDFInMemoryDataSource)
NS_INTERFACE_MAP_ENTRY(nsIRDFPropagatableDataSource)
NS_INTERFACE_MAP_ENTRY(nsIRDFPurgeableDataSource)
NS_INTERFACE_MAP_ENTRY(rdfIDataSource)
NS_INTERFACE_MAP_END
////////////////////////////////////////////////////////////////////////
#ifdef PR_LOGGING
void
InMemoryDataSource::LogOperation(const char* aOperation,
nsIRDFResource* aSource,
nsIRDFResource* aProperty,
nsIRDFNode* aTarget,
bool aTruthValue)
{
if (! PR_LOG_TEST(gLog, PR_LOG_NOTICE))
return;
nsXPIDLCString uri;
aSource->GetValue(getter_Copies(uri));
PR_LogPrint
("InMemoryDataSource(%p): %s", this, aOperation);
PR_LogPrint
(" [(%p)%s]--", aSource, (const char*) uri);
aProperty->GetValue(getter_Copies(uri));
char tv = (aTruthValue ? '-' : '!');
PR_LogPrint
(" --%c[(%p)%s]--", tv, aProperty, (const char*) uri);
nsCOMPtr<nsIRDFResource> resource;
nsCOMPtr<nsIRDFLiteral> literal;
if ((resource = do_QueryInterface(aTarget)) != nsnull) {
resource->GetValue(getter_Copies(uri));
PR_LogPrint
(" -->[(%p)%s]", aTarget, (const char*) uri);