gecko-dev/dom/base/nsPropertyTable.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
/**
* nsPropertyTable allows a set of arbitrary key/value pairs to be stored
* for any number of nodes, in a global hashtable rather than on the nodes
* themselves. Nodes can be any type of object; the hashtable keys are
* nsIAtom pointers, and the values are void pointers.
*/
#include "nsPropertyTable.h"
#include "mozilla/MemoryReporting.h"
#include "PLDHashTable.h"
#include "nsError.h"
#include "nsIAtom.h"
struct PropertyListMapEntry : public PLDHashEntryHdr {
const void *key;
void *value;
};
//----------------------------------------------------------------------
class nsPropertyTable::PropertyList {
public:
PropertyList(nsIAtom* aName,
NSPropertyDtorFunc aDtorFunc,
void* aDtorData,
bool aTransfer);
~PropertyList();
// Removes the property associated with the given object, and destroys
// the property value
bool DeletePropertyFor(nsPropertyOwner aObject);
// Destroy all remaining properties (without removing them)
void Destroy();
bool Equals(nsIAtom *aPropertyName)
{
return mName == aPropertyName;
}
size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
nsCOMPtr<nsIAtom> mName; // property name
PLDHashTable mObjectValueMap; // map of object/value pairs
NSPropertyDtorFunc mDtorFunc; // property specific value dtor function
void* mDtorData; // pointer to pass to dtor
bool mTransfer; // whether to transfer in
// TransferOrDeleteAllPropertiesFor
PropertyList* mNext;
};
void
nsPropertyTable::DeleteAllProperties()
{
while (mPropertyList) {
PropertyList* tmp = mPropertyList;
mPropertyList = mPropertyList->mNext;
tmp->Destroy();
delete tmp;
}
}
void
nsPropertyTable::DeleteAllPropertiesFor(nsPropertyOwner aObject)
{
for (PropertyList* prop = mPropertyList; prop; prop = prop->mNext) {
prop->DeletePropertyFor(aObject);
}
}
nsresult
nsPropertyTable::TransferOrDeleteAllPropertiesFor(nsPropertyOwner aObject,
nsPropertyTable *aOtherTable)
{
nsresult rv = NS_OK;
for (PropertyList* prop = mPropertyList; prop; prop = prop->mNext) {
if (prop->mTransfer) {
auto entry = static_cast<PropertyListMapEntry*>
(prop->mObjectValueMap.Search(aObject));
if (entry) {
rv = aOtherTable->SetProperty(aObject, prop->mName,
entry->value, prop->mDtorFunc,
prop->mDtorData, prop->mTransfer);
if (NS_FAILED(rv)) {
DeleteAllPropertiesFor(aObject);
aOtherTable->DeleteAllPropertiesFor(aObject);
break;
}
prop->mObjectValueMap.RemoveEntry(entry);
}
}
else {
prop->DeletePropertyFor(aObject);
}
}
return rv;
}
void
nsPropertyTable::Enumerate(nsPropertyOwner aObject,
NSPropertyFunc aCallback, void *aData)
{
PropertyList* prop;
for (prop = mPropertyList; prop; prop = prop->mNext) {
auto entry = static_cast<PropertyListMapEntry*>
(prop->mObjectValueMap.Search(aObject));
if (entry) {
aCallback(const_cast<void*>(aObject.get()), prop->mName, entry->value,
aData);
}
}
}
void
nsPropertyTable::EnumerateAll(NSPropertyFunc aCallBack, void* aData)
{
for (PropertyList* prop = mPropertyList; prop; prop = prop->mNext) {
for (auto iter = prop->mObjectValueMap.Iter(); !iter.Done(); iter.Next()) {
auto entry = static_cast<PropertyListMapEntry*>(iter.Get());
aCallBack(const_cast<void*>(entry->key), prop->mName, entry->value,
aData);
}
}
}
void*
nsPropertyTable::GetPropertyInternal(nsPropertyOwner aObject,
nsIAtom *aPropertyName,
bool aRemove,
nsresult *aResult)
{
NS_PRECONDITION(aPropertyName && aObject, "unexpected null param");
nsresult rv = NS_PROPTABLE_PROP_NOT_THERE;
void *propValue = nullptr;
PropertyList* propertyList = GetPropertyListFor(aPropertyName);
if (propertyList) {
auto entry = static_cast<PropertyListMapEntry*>
(propertyList->mObjectValueMap.Search(aObject));
if (entry) {
propValue = entry->value;
if (aRemove) {
// don't call propertyList->mDtorFunc. That's the caller's job now.
propertyList->mObjectValueMap.RemoveEntry(entry);
}
rv = NS_OK;
}
}
if (aResult)
*aResult = rv;
return propValue;
}
nsresult
nsPropertyTable::SetPropertyInternal(nsPropertyOwner aObject,
nsIAtom *aPropertyName,
void *aPropertyValue,
NSPropertyDtorFunc aPropDtorFunc,
void *aPropDtorData,
bool aTransfer,
void **aOldValue)
{
NS_PRECONDITION(aPropertyName && aObject, "unexpected null param");
PropertyList* propertyList = GetPropertyListFor(aPropertyName);
if (propertyList) {
// Make sure the dtor function and data and the transfer flag match
if (aPropDtorFunc != propertyList->mDtorFunc ||
aPropDtorData != propertyList->mDtorData ||
aTransfer != propertyList->mTransfer) {
NS_WARNING("Destructor/data mismatch while setting property");
return NS_ERROR_INVALID_ARG;
}
} else {
propertyList = new PropertyList(aPropertyName, aPropDtorFunc,
aPropDtorData, aTransfer);
propertyList->mNext = mPropertyList;
mPropertyList = propertyList;
}
// The current property value (if there is one) is replaced and the current
// value is destroyed
nsresult result = NS_OK;
auto entry = static_cast<PropertyListMapEntry*>
(propertyList->mObjectValueMap.Add(aObject, mozilla::fallible));
if (!entry)
return NS_ERROR_OUT_OF_MEMORY;
// A nullptr entry->key is the sign that the entry has just been allocated
// for us. If it's non-nullptr then we have an existing entry.
if (entry->key) {
if (aOldValue)
*aOldValue = entry->value;
else if (propertyList->mDtorFunc)
propertyList->mDtorFunc(const_cast<void*>(entry->key), aPropertyName,
entry->value, propertyList->mDtorData);
result = NS_PROPTABLE_PROP_OVERWRITTEN;
}
else if (aOldValue) {
*aOldValue = nullptr;
}
entry->key = aObject;
entry->value = aPropertyValue;
return result;
}
nsresult
nsPropertyTable::DeleteProperty(nsPropertyOwner aObject,
nsIAtom *aPropertyName)
{
NS_PRECONDITION(aPropertyName && aObject, "unexpected null param");
PropertyList* propertyList = GetPropertyListFor(aPropertyName);
if (propertyList) {
if (propertyList->DeletePropertyFor(aObject))
return NS_OK;
}
return NS_PROPTABLE_PROP_NOT_THERE;
}
nsPropertyTable::PropertyList*
nsPropertyTable::GetPropertyListFor(nsIAtom* aPropertyName) const
{
PropertyList* result;
for (result = mPropertyList; result; result = result->mNext) {
if (result->Equals(aPropertyName)) {
break;
}
}
return result;
}
//----------------------------------------------------------------------
nsPropertyTable::PropertyList::PropertyList(nsIAtom *aName,
NSPropertyDtorFunc aDtorFunc,
void *aDtorData,
bool aTransfer)
: mName(aName),
mObjectValueMap(PLDHashTable::StubOps(), sizeof(PropertyListMapEntry)),
mDtorFunc(aDtorFunc),
mDtorData(aDtorData),
mTransfer(aTransfer),
mNext(nullptr)
{
}
nsPropertyTable::PropertyList::~PropertyList()
{
}
void
nsPropertyTable::PropertyList::Destroy()
{
// Enumerate any remaining object/value pairs and destroy the value object.
if (mDtorFunc) {
for (auto iter = mObjectValueMap.Iter(); !iter.Done(); iter.Next()) {
auto entry = static_cast<PropertyListMapEntry*>(iter.Get());
mDtorFunc(const_cast<void*>(entry->key), mName, entry->value, mDtorData);
}
}
}
bool
nsPropertyTable::PropertyList::DeletePropertyFor(nsPropertyOwner aObject)
{
auto entry =
static_cast<PropertyListMapEntry*>(mObjectValueMap.Search(aObject));
if (!entry)
return false;
void* value = entry->value;
mObjectValueMap.RemoveEntry(entry);
if (mDtorFunc)
mDtorFunc(const_cast<void*>(aObject.get()), mName, value, mDtorData);
return true;
}
size_t
nsPropertyTable::PropertyList::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
{
size_t n = aMallocSizeOf(this);
n += mObjectValueMap.ShallowSizeOfExcludingThis(aMallocSizeOf);
return n;
}
size_t
nsPropertyTable::SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
size_t n = 0;
for (PropertyList *prop = mPropertyList; prop; prop = prop->mNext) {
n += prop->SizeOfIncludingThis(aMallocSizeOf);
}
return n;
}
size_t
nsPropertyTable::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
/* static */
void
nsPropertyTable::SupportsDtorFunc(void *aObject, nsIAtom *aPropertyName,
void *aPropertyValue, void *aData)
{
nsISupports *propertyValue = static_cast<nsISupports*>(aPropertyValue);
NS_IF_RELEASE(propertyValue);
}