There is an issue where gifs with many frames cannot be loaded, as each
bitmap is sent over IPC using a separate file descriptor, and there is
limit on the maximum number of descriptors per IPC message. Thus, trying
to load gifs with more than 64 frames (the current limit) causes the
image decoder process to die.
This commit introduces the BitmapSequence class, which is a thin wrapper
around the type Vector<Optional<NonnullRefPtr<Gfx::Bitmap>>> and
provides an IPC encode/decode routine that collates all bitmap data into
a single buffer so that only a single file descriptor is required per
IPC transfer, even if multiple frames are being sent.
Before this change, we were passing them as Gfx::ShareableBitmap. The
problem is that shareable bitmaps keep their underlying file descriptor
open, so that they can be shared again with someone else.
When a Gfx::Bitmap is decoded from an IPC message, the file descriptor
is closed and recovered immediately.
This fixes an issue where we'd accumulate one file descriptor for every
image decoded. This eventually led to descriptor starvation after enough
images were loaded and still referenced at the same time.
ImageDecoder now queues up image decoding requests and returns the
images back to the caller later. ImageDecoderClient has a new
promise-based API that allows callers to attach their own resolve/reject
handlers to the responses from ImageDecoder.
This patch removes the IPC endpoint numbers that needed to be specified
in the IPC files. Since the string hash is a (hopefully) collision free
number that depends on the name of the endpoint, we now use that
instead. :^)
Additionally, endpoint magic is now treated as a u32, because endpoint
numbers were never negative anyway.
For cases where the endpoint number does have to be hardcoded (a current
case is LookupServer because the endpoint number must be known in LibC),
the syntax has been made more explicit to avoid confusing those
unfamiliar. To hardcode the endpoint magic, the following syntax is now
used:
endpoint EndpointName [magic=1234]
This patch removes the IPC endpoint numbers that needed to be specified
in the IPC files. Since the string hash is a (hopefully) collision free
number that depends on the name of the endpoint, we now use that
instead. :^)
