The old code assumes that it's OK to use nsAString::BeginWriting() to write
past the string's logical length if the string has enough capacity. This is
bogus, because the string doesn't know of data written past its logical
length.
The BulkWrite API has been created precisely for this purpose and allows
orderly capacity-aware low-level writes to the string.
MozReview-Commit-ID: BYQHl8Z9Fbd
Differential Revision: https://phabricator.services.mozilla.com/D3886
--HG--
extra : moz-landing-system : lando
The old code assumes that it's OK to use nsAString::BeginWriting() to write
past the string's logical length if the string has enough capacity. This is
bogus, because the string doesn't know of data written past its logical
length.
The BulkWrite API has been created precisely for this purpose and allows
orderly capacity-aware low-level writes to the string.
MozReview-Commit-ID: BYQHl8Z9Fbd
Differential Revision: https://phabricator.services.mozilla.com/D3886
--HG--
extra : moz-landing-system : lando
The renaming here is like this:
SetStringBuffer -> SetKnownLiveStringBuffer
SetEphemeralStringBuffer -> SetStringBuffer
SetOwnedString -> SetKnownLiveString
SetOwnedAtom -> SetKnownLiveAtom
This should make it clearer what the lifetime expectations are on the caller side.
MozReview-Commit-ID: ERHbB3r6paN
Currently nsAtom::mString points to the interior of an nsStringBuffer. For
static atoms this requires the use of nsFakeStringBuffer, which is pretty
gross.
This patch changes things so that nsAtom::mString points to a static char
buffer for static atoms. This simplifies a number of things:
- nsFakeStringBuffer and CheckStaticAtomSizes are no longer needed.
- FakeBufferRefCountHelper is no longer needed.
- nsAtom's constructor for static atoms is simpler.
- RegisterStaticAtoms() is simpler.
On the flip-side, a couple of things get more complicated.
- nsAtom::ToString() treats static and dynamic atoms differently.
- nsAtom::GetStringBuffer() is now only valid for dynamic atoms. This
function is only used in two places, both involving DOMString, so those
locations are updated appropriately. This also requires updating some other
code assigning nsStrings to DOMStrings, because we can't assume that
nsStrings are shared.
On Linux64 this change reduces the size of the binary by 8752 B, and moves
81968 B from the .data to the .rodata section, where it can be shared between
processes.
--HG--
extra : rebase_source : 0f6fcdec1c525aa66222e208b66a9f9026f69bcb
Sylvestre Ledru
Henri Sivonen
Andreea Pavel
Boris Zbarsky
Nicholas Nethercote
Ben Kelly
Andrea Marchesini