Don't send any preferences that have a string value that is longer
than MAX_ADVISABLE_PREF_LENGTH. This is intended to mitigate OOM
issues, as I've seen a parent process crash trying to create a 100mb
message to send to the child. Such users likely cannot use e10s at
all.
This has a test for all combinations of setting the default and user
values of a preference to large or small string values, or not setting
them at all.
I manually verified that filtering out preferences reduces the size of
the IPC::Message that is sent to the child by printing out the size of
the reply message in PContentParent::OnMessageReceived().
Returning outparams with UniquePtr is not convenient or idiomatic, so in
addition to removing nsAutoArrayPtr usage, let's return a UniquePtr from
the function directly.
The original motivation for the Iterator/RemovingIterator split was that
PLDHashTable Checker class would treat them differently. But that didn't end up
happening (see bug 1131308). So this patch merges them. This is a small code
size win now but it will become bigger when I add iterators to nsTHashTable and
nsBaseHashtable.
The only complication is that PLDHashTable::Iter() is now non-const, which is
a problem if you use it in a const method. So I added PLDHashTable::ConstIter()
which is used in just two places. It's a bit of a hack -- effectively a
const_cast -- but I don't think it's too bad.
It's no longer needed now that entry storage isn't allocated there. (The other
possible causes of failures in that function are less interesting and simply
crashing is a reasonable thing to do for them.)
This also makes PL_DNewHashTable() infallible, so I removed some
now-unnecessary checks of its result.
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.
Because it's no longer needed now that entry storage isn't allocated there.
(The other possible causes of failures are much less interesting and simply
crashing is a reasonable thing to do for them.)
This also makes PL_DNewHashTable() infallible.
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.
Currently the setting of PLDHashTable::ops is very haphazard.
- PLDHashTable has no constructor, so it's not auto-nulled, so lots of places
null it themselves.
- In the fallible PLDHashTable::Init() function, if the entry storage
allocation fails we'll be left with a table that has |ops| set -- indicating
it's been initialized -- but has null entry storage. I'm not certain this can
cause problems but it feels unsafe, and some (but not all) callers of Init()
null it on failure.
- PLDHashTable does not null |ops| in Finish(), so some (but not all) callers
do this themselves.
This patch makes things simpler.
- It adds a constructor that zeroes |ops|.
- It modifies Init() so that it only sets |ops| once success is ensured.
- It zeroes |ops| in Finish().
- Finally, it removes all the now-unnecessary |ops| nulling done by the users
of PLDHashTable.
