The in-memory HTTP Fetch cache currently keeps the realm which created
each cache entry alive indefinitely. This patch migrates this cache to
LibHTTP, to ensure it is completely unaware of any JS objects.
Now that we are not interacting with Fetch response objects, we can no
longer use Streams infrastructure to pipe the response body into the
Fetch response. Fetch also ultimately creates the cache response once
the HTTP response headers have arrived. So the LibHTTP cache will hold
entries in a pending list until we have received the entire response
body. Then it is moved to a completed list and may be used thereafter.
Previously, unbuffered requests were only available as a special mode
for EventSource. With this change, they are enabled by default, which
means chunks can be read from the stream as soon as they arrive.
This unlocks some interesting possibilities, such as starting to parse
HTML documents before the entire response has been received (that, in
turn, allows us to initiate subresource fetches earlier or begin
executing scripts sooner), or start rendering videos before they are
fully downloaded.
Co-authored-by: Timothy Flynn <trflynn89@pm.me>
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
