This allows reusing the asynchrnous fetch mechanism that we use for page
resources and is likely a step toward removing the `FetchThread`.
Benefits:
- Reduces IPC traffic during navigation. Now instead of bouncing
between the constellation and the `ScriptThread` responses are sent
directly to the `ScriptThread`.
- Allows cancelling loads after redirects, which was not possible
before.
There is the question of what to do when a redirect is cross-origin
(#23037). This currently isn't handled properly as the `Constellation`
sends data to the same `Pipeline` that initiated the load. This change
doesn't fix this issue, but does make it more possible for the
`ScriptThread` to shut down the pipeline and ask the `Constellation` to
replace it with a new one.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Previously, senders and receivers to different kinds of event loops (the
main `ScriptThread`, different types of workers) used a rust `trait`
mechanism to implement dynamic behavior. This led to having many unused
implementations of this `trait`. This change moves to using an `enum`
based approach for these senders and receivers and removes all of the
dead code.
In addition, to allowing for use of rust's dead code detection, it
simplifies the code a great deal. All of these generic senders and
receivers are moved to the `messaging.rs` file and given proper
documentation.
Finally, empty an `JSTraceable` implementation is made for all
crossbeam `Sender<...>`s to avoid having to manually skip them everytime
they are included in structs. The pre-existing empty `MallocSizeOf`
implementation is used more thoroughly.
Other unecessary wrappers around these senders and receivers are removed
as well.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Instead of creating a type for each `TaskSource` variety have each `TaskSource`
hold the same kind of sender (this was inconsistent before, but each
sender was effectively the same trait object), a pipeline, and a
`TaskSourceName`. This elminates the need to reimplement the same
queuing code for every task source.
In addition, have workers hold their own `TaskManager`. This allows just
exposing the manager on the `GlobalScope`. Currently the `TaskCanceller`
is different, but this will also be eliminated in a followup change.
This is a the first step toward having a shared set of `Sender`s on
`GlobalScope`.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Create two new data structures in the `script` crate to hold senders and
receiver:
- `ScriptThreadSenders`: holds all outgoing channels from the
`ScriptThread` including a channel to the `ScriptThread` itself. The
ultimate goal with this is to reduce duplication by giving a boxed
version of this this to `Window`s.
- `ScriptThradReceivers`: holds all incoming channels to the
`ScriptThread`. This isn't cloenable like the senders. This is used to
abstract away `recv()` and `try_recv()` methods used to make the
`ScriptThread` event loop easier to read.
In addition:
- The many duplicated `ScriptThread` self-senders for the `TaskManager`
have been removed and, in general, a lot of boilerplate is removed as
well.
- Visibilty of all methods affected by this change is changed to
`pub(crate)` in order to take advantage of dead code detection. Some
dead code produced from macros is removed.
- Some conversion code is refactord into implementations of the `From`
trait.
- The names of channels uses a standard "sender" and "receiver" naming
as well as trying to be descriptive of where they go in `ScriptThread`
as well as `InitialScriptState`
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
