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Bug 1172761 (part 2) - Remove PL_DHashTableEnumerator use from nsPersistentProperties. r=froydnj.

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The old code attempted to deal with any OOMs during this enumeration --
OOMs are possible because it's growing an nsCOMArray -- but failed to do so
correctly.

- It didn't check the return value of AppendObject().

- It did check that EntryCount() matched the return value of
  PL_DHashTableEnumerate(), but that's always (and vacuously) true.

The new code just returns NS_ERROR_OUT_OF_MEMORY if AppendObject() fails; this
is trivial now that it uses an iterator and doesn't have to call out to another
function.
This commit is contained in:
Nicholas Nethercote 2015-06-10 13:07:40 -07:00
parent 97aa68b77f
commit 977758d61c
1 changed files with 11 additions and 22 deletions
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33
xpcom/ds/nsPersistentProperties.cpp
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@ -563,25 +563,6 @@ nsPersistentProperties::GetStringProperty(const nsACString& aKey,
return NS_OK;
}
static PLDHashOperator
AddElemToArray(PLDHashTable* aTable, PLDHashEntryHdr* aHdr,
uint32_t aIndex, void* aArg)
{
nsCOMArray<nsIPropertyElement>* props =
static_cast<nsCOMArray<nsIPropertyElement>*>(aArg);
PropertyTableEntry* entry =
static_cast<PropertyTableEntry*>(aHdr);
nsPropertyElement* element =
new nsPropertyElement(nsDependentCString(entry->mKey),
nsDependentString(entry->mValue));
props->AppendObject(element);
return PL_DHASH_NEXT;
}
NS_IMETHODIMP
nsPersistentProperties::Enumerate(nsISimpleEnumerator** aResult)
{
@ -591,9 +572,17 @@ nsPersistentProperties::Enumerate(nsISimpleEnumerator** aResult)
props.SetCapacity(mTable.EntryCount());
// Step through hash entries populating a transient array
uint32_t n = PL_DHashTableEnumerate(&mTable, AddElemToArray, (void*)&props);
if (n < mTable.EntryCount()) {
return NS_ERROR_OUT_OF_MEMORY;
PLDHashTable::Iterator iter(&mTable);
while (iter.HasMoreEntries()) {
auto entry = static_cast<PropertyTableEntry*>(iter.NextEntry());
nsRefPtr<nsPropertyElement> element =
new nsPropertyElement(nsDependentCString(entry->mKey),
nsDependentString(entry->mValue));
if (!props.AppendObject(element)) {
return NS_ERROR_OUT_OF_MEMORY;
}
}
return NS_NewArrayEnumerator(aResult, props);