Root cause of the post-tab lag: the GPUI 16 ms timer was calling
`WebSurfaceRuntime::ensure_tab` and `tick` on the UI thread, and each
call did a synchronous `serde_json` write plus `read_line` against the
Servo sidecar over stdin/stdout. With even one visible tab, every
frame stalled on cross-process IPC.
Introduce `web_surface_worker.rs` — a per-profile worker thread that
owns the `ServoLiveClient`, drains a coalescing request queue
(latest Ensure/Poll per tab wins, no unbounded growth), and ships
results back through a `std::sync::mpsc` channel. `WebSurfaceRuntime`
now submits work non-blockingly and drains responses in `tick`; the
UI thread never blocks on the sidecar.
Adjacent in-flight cleanup riding along: hardware IOSurface
rendering-context completion (sidecar `live_protocol`,
`hardware_rendering_context`, GPUI BGRA surface shader), CSS viewport
size + device pixel ratio plumbing into `ServoLiveFrame`, and the
Send opt-ins for `CVPixelBuffer`-bearing types so frames can cross
the thread boundary.
`webview.paint()` dispatches a render command to Servo's paint thread
asynchronously, so the subsequent `read_to_image()` raced the paint
thread and reliably returned cleared-white pixels on data: URLs (T10.8).
Clear `has_pending_frame` before dispatching paint, then spin the Servo
event loop until `notify_new_frame_ready` re-arms it or 32 ms elapse
(override via `ELY_PAINT_BARRIER_MS`). Bench: software path now ships
real RGBA bytes for 60 frames instead of all-white.
`HardwareOffscreenContext` was vendored in 048c5df but the host's
per-webview `new_rendering_context` still hard-wired
`servo::SoftwareRenderingContext`. This commit threads a
`RenderingContextKind` enum through the host so existing call sites
keep their software path, and new callers can opt into the hardware
path through `SoftwareServoHost::new_with_config_dir_and_kind(...)`.
Three changes, kept tightly scoped:
* `runtime.rs` gains a public `RenderingContextKind { Software,
Hardware }` enum and a new constructor that takes it. The
existing `new` and `new_with_config_dir` keep their signatures
and default to `Software`, so the sidecar binary and the
integration tests pick up zero behavioural change. The
private `new_rendering_context` moves from a free function to a
`&self` method so it can read `self.rendering_context_kind` and
dispatch — `Software` constructs `SoftwareRenderingContext` as
before, `Hardware` constructs the vendored
`HardwareOffscreenContext`. When the `hardware-render` feature
isn't compiled in, the `Hardware` arm returns
`ServoHostError::HardwareRenderUnavailable` instead of silently
falling back; the new constructor also rejects the request
up-front before touching the global Servo runtime flag.
* `error.rs` gains `HardwareRenderUnavailable` so the wrong-feature
path is a typed error, not a panic.
* `lib.rs` exports `RenderingContextKind` alongside
`SoftwareServoHost` so downstream code (next commit will be the
sidecar's `--rendering-context` CLI flag and the live.rs
plumbing) can name the variant directly.
This is purely an extension point — no existing call path changes,
no existing test asserts on the new enum. The next commit will add
the sidecar CLI flag and wire `live.rs::run_live` to pass the kind
through to the host so users can pick the path at startup. The
follow-up commits then extract the IOSurface from the hardware
surfman surface and bridge it across the IPC channel to GPUI's
Metal renderer, deleting the host-side `Vec<u8>` from the per-frame
hot path entirely (full plan in docs/t10-iosurface-plan.md).
cargo test -p ely_servo_host --features servo-engine --lib: 2 passed.
cargo test -p ely_servo_host --features servo-engine --test sidecar: 9 passed.
cargo test -p ely_servo_host --features servo-engine,hardware-render
--test hardware_rendering_context: 1 passed.
cargo test --bin ely_app: 120 passed, 0 failed, 2 ignored.
Servo's hit-test silently absorbs notify_input_event on a hidden or
unfocused WebView. Today show()+focus() are called at creation and on
the first-navigate rebuild, but every later sibling-WebView creation
also calls focus() — silently stealing focus from the foreground tab.
load() (later navigates), resize, set_page_zoom, and paint never
re-focus, so a click on the visible tab can land on an unreachable
WebView and disappear.
Move the invariant from a state spread across creation/navigation/
tab-switching into a property of the dispatch path itself: a private
webview_for_input(id) helper re-asserts show()+focus() and returns
the WebView; click/hover/drag/touch_tap/scroll/type_text all go
through it. The cosmetic show/focus calls in create_webview_in_context
and the navigate-rebuild branch stay (first-frame paint), now annotated
to point to webview_for_input as the input-path owner.
Not a complete fix on its own. focus() goes through constellation_proxy
asynchronously (servo crate webview.rs:352), so debug_assert!(focused())
right after focus() would race the constellation — doc comment is the
only guard. Sidecar integration tests pass 9/9 but only exercise
single-WebView sessions; multi-tab focus stealing on Google / YouTube /
Twitter still needs human verification in the live shell. Linus's
critique of the GPUI-side data structure (PerTabSurface Option-as-queue
+ Ensure bundling config+input+frame) is a separate layer untouched
by this change.
Pre-existing tests/software_host.rs::manages_real_servo_webview_lifecycle
already times out on https://servo.org/ with state=Complete but
has_pending_frame=false on b8795bf without this change, so unrelated.
Root cause: Servo's WebView is hidden+unfocused by default. notify_input_event
on a hidden WebView runs paint() hit-test, which returns no hit, and Servo
silently absorbs the event as "already handled". Eleven prior commits all
patched the GPUI side of input forwarding while every event landed in
exactly that black hole.
Fix: webview.show() + webview.focus() immediately after WebViewBuilder::build
in create_webview_in_context, and again in navigate() only on the
should_create_initial_document branch (the load() branch keeps existing
visibility+focus, otherwise a background tab finishing navigation would
steal focus from the foreground tab — Linus correctness ask).
Also unblocks the sidecar binary build, which had been frozen at the
May 9 13:53 stale binary because servo-engine feature was broken on two
fronts:
- ServoHost trait was missing the hover() method that the SoftwareServoHost
impl declared (regression from "Plug three holes" commit eb58ce7).
- Servo SDK renamed Key::Enter / Backspace / Tab / Escape / Delete /
Arrow{Up,Down,Left,Right} / Home / End / Page{Up,Down} to
Key::Named(NamedKey::*). keyboard.rs updated to match.
Sidecar binary rebuilt: 335 MB at May 10 01:44. The earlier 11 commits
were never reaching users because they couldn't recompile the sidecar
without these two upstream-API repairs.
1. Scroll no longer wipes keyboard focus. Servo holds DOM focus across
wheel events; the shell was clearing keyboard_focus and typed_texts
on every scroll, so a focused input went deaf the moment the user
scrolled. Scroll still drops the buffered click point because that
coordinate is captured against the pre-scroll viewport.
2. Mouse-down hands focus to the shell's root focus handle (in
addition to mouse-up's existing click forwarding). The user can now
start typing the moment they press the page, instead of having to
first complete a click round-trip to escape the omnibar's focus.
3. Sidecar hover() honors the requesting webview_id instead of
defaulting to the first webview in the map, so multi-tab sidecars
no longer pipe every hover into tab #1.
Without continuous MouseMove events, Servo never updates hover state:
no cursor changes over links, no :hover CSS effects, no mouseenter
JavaScript events. The web page appears completely non-interactive.
Track mouse position from GPUI on_mouse_move through the full IPC
pipeline to Servo. Hover position is included with each ensure
request so Servo updates hover state at frame rate (~60fps).
ZacharyZhang-NY