This change splits PLDHashTable::Iterator::NextEntry() into two separate
functions, which allow you to get the current element and advance the iterator
separately, which means you can use a for-loop to iterate instead of a
while-loop.
As part of this change, the internals of PLDHashTable::Iterator were
significantly changed and simplified (and modelled after js::HashTable's
equivalent code). It's no longer duplicating code from PL_DHashTableEnumerator.
The chaos mode code was a casualty of this, but given how unreliable that code
has proven to be (see bug 1173212, bug 1174046) this is for the best. (We can
reimplement chaos mode once PLDHashTable::Iterator is back on more solid
footing again, if we think it's important.)
All these changes will make it much easier to add an alternative Iterator that
removes elements, which was turning out to be difficult with the prior code.
In order to make the for-loop header usually fit on a single line, I
deliberately renamed a bunch of things to have shorter names.
In summary, you used to write this:
PLDHashTable::Iterator iter(&table);
while (iter.HasMoreEntries()) {
auto entry = static_cast<FooEntry*>(iter.NextEntry());
// ... do stuff with |entry| ...
}
// iter's scope extends beyond here
and now you write this:
for (auto iter = table.Iter(); !iter.Done(); iter.Next()) {
auto entry = static_cast<FooEntry*>(iter.Get());
// ... do stuff with |entry| ...
}
// iter's scope doesn't reach here
This patch converts easy cases, i.e. where the PL_DHashTableInit() call occurs
in a constructor and the PL_DHashTableFinish() call occurs in a destructor.
This patch converts easy cases, i.e. where the PL_DHashTableInit() call occurs
in a constructor and the PL_DHashTableFinish() call occurs in a destructor.
I kept all the existing PL_DHashTableAdd() calls fallible, in order to be
conservative, except for the ones in nsAtomTable.cpp which already were
followed immediately by an abort on failure.
I kept all the existing PL_DHashTableAdd() calls fallible, in order to be
conservative, except for the ones in nsAtomTable.cpp which already were
followed immediately by an abort on failure.
It feels safer to use a function with a new name, rather than just changing the
behaviour of the existing function.
For most of these cases the PL_DHashTableLookup() result was checked with
PL_DHASH_ENTRY_IS_{FREE,BUSY} so the conversion was easy. A few of them
preceded that check with a useless null check, but the intent of these was
still easy to determine.
I'll do the trickier ones in subsequent patches.
