The Storage panel expects storesUpdate messages after watched storage
changes. Summarize committed IndexedDB mutation logs into DevTools paths
and forward them through WebContent so Firefox can refresh database,
object-store, and record rows without polling.
Firefox's behaviour is less than ideal here. A lot of things don't
update automatically even inspecting a page in Firefox. Some
things (like new databases) won't show up until you fully refresh the
page. So that makes it a bit hard to know that we're doing things
correctly. As far as I can tell, we are at least behaving as well as
Firefox requires.
We do have one workaround: Firefox doesn't display record updates
without a manual refresh, and in fact any change messages for them show
up as rows in the host's database table. So for now, we filter them out
to avoid visual weirdness in the inspector.
Firefox asks the storage watcher for an indexed-db resource before it
shows IndexedDB entries in the Storage panel. Add an IndexedDB actor and
serialize the live LibWeb database registry on demand, so WebContent can
return the host tree and table rows without duplicating database state.
Use the LibWeb inspection helpers to read IndexedDB internals, and keep
the Firefox protocol shape in LibDevTools. WebContent only forwards the
serialized response over the existing DevTools IPC path.
Apply pinch zoom deltas to the compositor's visual viewport transform
so the currently presented display list can respond without waiting for
the WebContent main thread. Keep the normal WebContent pinch event path
so the real VisualViewport state and DOM-visible events catch up after.
Only take the compositor path when async scrolling is enabled and there
are no blocking wheel listeners, since pinch zoom dispatches a synthetic
wheel event that script may cancel. Coalesce queued pinch events in
WebContent so main-thread catch-up can adopt multiple gesture deltas
together.
Use the compositor visual viewport transform for wheel hit testing and
consume wheel deltas as visual viewport pan while zoomed. Scale the
handoff to layout viewport scrolling by the inverse visual viewport
scale, so touchpad momentum does not jump when the visual viewport hits
an edge.
Same-document navigations now commit synchronously in WebContent, while
the UI process mirror learns about them over asynchronous IPC. A stale
UI seed could be accepted back into a live non-initial document and
overwrite its latest entry, making queued traversals target unreachable
entries.
Share descriptor comparison helpers between LibWeb and LibWebView.
Reject stale top-level seeds against the active document latest entry,
and let the UI process adopt WebContent current snapshots when a seed is
rejected. Test-only session history dumps now first send WebContent
current state synchronously, so dumps observe the converged state.
Allow post-load UI seeds to carry UI-owned nested histories that the
freshly loaded top-level document has not reconstructed yet. Add unit
coverage for matching those seeds while still checking top-level state.
Use the LibWebView history mirror to preserve traversable session
history across WebContent process swaps. WebContent reports snapshots to
the UI process, and new renderers can be seeded from the mirror.
Browser back and forward now resolve through the UI-owned used history
steps. WebContent still runs the spec traversal path when the current
renderer has enough matching state to do so.
Handle canceled and no-op UI navigations without leaving speculative
history entries or pending WebDriver waits behind. Preserve traversal
precheck state across synchronous IPC shutdown, and avoid overwriting a
restored target entry's persisted scroll state before the document has
adopted that entry.
Add Internals.deleteAllCookies(), backed by an async WebContent to
browser request and ack pair. CookieJar can now clear transient and
persisted cookies. Note that we only delete all cookies associated
with the current URL so that tests are able to run in parallel with
one another without impacting shared cookie state.
Firefox keeps the Storage panel current by sending store update packets
when localStorage or sessionStorage changes. Forward successful Web
Storage mutations to the storage actors and emit the matching update or
clear packet.
Use listener IDs for storage updates so the local and session storage
actors can subscribe independently.
Firefox exposes localStorage and sessionStorage through the same
storage actor protocol used by cookies. Add matching resources for the
current tab so the Storage panel can list key/value pairs.
Read the values through WebContent rather than directly from the
browser process. Session storage lives in LibWeb, and using the same
path for both stores keeps the actor independent of the backing store.
Remove internals.loadTestVariants and the IPC forwarding that reported
variant metadata back to WebView. test-web now identifies WPT variants
during collection, so no loaded document needs to expose this test-only
hook.
Enable -Wexit-time-destructors for all in-tree library targets and
update process-lifetime library statics so they no longer register
exit-time destructors. Long-lived caches, lookup tables, singleton
registries, and generated constants now use NeverDestroyed or leaked
references where the data is intended to live until process exit.
Update LibWeb, LibLine, and the binding generators so regenerated
sources follow the same rule instead of reintroducing destructed
statics.
Compositor recovery recreated contexts and replayed viewport sizes,
but it left the restarted helper with the default display metadata. A
recovered context could fall back to a 60 Hz timer instead of the
window's current display id and refresh rate until the frontend later
observed a screen change.
Store the display id in the shared view state, alongside the existing
maximum frame rate, and replay both values while restoring view state
after reconnect.
Page-presenting compositor contexts still carried a separate tagged ID
namespace and Browser-side page/context maps even though page IDs are
now allocated globally by the UI process. That made context
registration keep two ways to describe the same relationship and
forced compositor IPC to pass an extra presentation bit.
Use each page ID directly as its page-presenting compositor context ID
and allocate non-page compositor contexts from the same Browser-owned
counter. The registration path now sends only the optional page ID, and
Compositor infers client presentation from that page ID.
Page IDs were allocated independently by each WebContent PageHost,
starting at zero for every process. That made them unsuitable as a
global identity for page-presenting compositor contexts, because the
same numeric page ID could exist in multiple WebContent processes.
Move page ID allocation to WebView::Application and initialize each
WebContent process with its browser-assigned first page ID over IPC.
New view requests now get a browser-assigned page ID before
WebContent creates the PageClient, and PageHost no longer owns a
local page counter.
This gives page-presenting compositor contexts a stable global page
identity, which will allow their context IDs to be derived from page
IDs and simplify compositor context allocation in a follow-up.
When an HTTPS response carries a Strict-Transport-Security header, the
received policy is now respected. Subsequent HTTP requests to a known
HSTS host are upgraded to HTTPS before the fetch algorithm makes
further decisions such as CORS and mixed content.
Fixes tpexpress.co.uk, where an XHR redirects HTTPS -> HTTP -> HTTPS,
relying on a HSTS policy received on the document response to avoid the
CORS failure.
Picking needs hit testing in the page process, where layout and event
targeting state live. Expose a small page-level query and WebContent IPC
entry point that returns the node id at a viewport position.
This lets DevTools ask WebContent what the picker is pointing at without
duplicating hit-test logic outside LibWeb.
Commit 218d82cb65 added support for
pasting text with the middle mouse button. But primary pasting is
actually meant to interact with the "selection" clipboard, not the
text clipboard.
Add IPC structures and requests for inspecting grid layout data from
WebContent.
WebView forwards the async replies to LibDevTools and exposes the grid
highlighter hooks used by the protocol layer.
Parse Firefox grid highlighter options in WebContent and store them with
the active grid highlight.
This lays the groundwork to allow shared workers, nested workers (i.e.
workers owned by workers) and service workers to function independently
of WebContent.
Track whether WebContent still needs a beforeunload check and let the
frontends immediately remove a tab or window when no prompt can be
shown. WebContent still receives the close request so pagehide, unload,
and cleanup steps can run.
When the visible view is removed immediately, keep detached ownership of
the WebContent page until it reports that the top-level traversable
closed. If no acknowledgement arrives, release detached ownership and
ask ProcessManager to shut down the unused WebContent process.
Notify the UI process with the solid canvas background color recorded
for the top-level document. This is the Canvas system color with the
effective document background composited over it, matching the color
used before normal painting.
Store that color on the view and use it when AppKit, Qt, and Gtk need
to fill areas exposed while an older bitmap is still on screen during a
window resize.
The browser previously treated the out-of-process Compositor as fatal.
Restart the shared Compositor from the browser process, reconnect
process-backed WebContent clients, recreate compositor contexts, restore
viewport state, and ask WebContent to repaint and republish canvas and
media resources. WebContent now marks its compositor connection lost,
returns conservative values for synchronous compositor queries while
reconnecting, and drops outgoing updates until the replacement transport
arrives.
Synchronous input queries through the compositor control connection now
use fallible IPC. If the Compositor exits after the open check or before
the sync reply arrives, scroll and mouse handling report that the
Compositor did not handle the event and let the normal WebContent
fallback run.
Mouse events queued while the Compositor is unavailable now fall back to
direct WebContent dispatch. This keeps input completion in step with the
pending-event queue.
Recovery is capped at three automatic restarts. If the restart limit is
exceeded, if restart, reconnect, or context recreation fails, or if the
replacement Compositor exits during active recovery, the browser crashes
instead of switching process-backed views to a fallback path.
We are moving toward an architecture where the browser owns a single
process that holds the GPU context, so Skia resources can be shared
across every renderer and WebContent processes can be sandboxed away
from direct GPU access. A dedicated Compositor helper process is the
first step. The earlier commits laid the foundation; this one turns the
helper on as a selectable backend, gated behind
--enable-compositor-process so the existing in-process path stays the
shipping default.
Default topology -- one compositor per WebContent, in-process:
+---------+
| Browser |
+---------+
/ | \
v v v
+---+ +---+ +---+ each WebContent runs its own
|WC | |WC | |WC | CompositorThread on a dedicated
|+C+| |+C+| |+C+| thread, with its own GPU context.
+---+ +---+ +---+
Opt-in topology -- one single-threaded Compositor, shared by all WCs:
+---------+ control +-------------------+
| Browser |<----------->| Compositor |
+---------+ | (single thread, |
/ | \ | single GPU ctx, |
v v v data | shared by all |
[WC] [WC] [WC] ---------->| connected WCs) |
+-------------------+
Three IPC channels carry the work in the opt-in topology. The
existing Browser<->WebContent channel gains context allocation.
A new Browser<->Compositor channel carries context lifetime,
viewport, UI input, and presentation acks plus backing-store and
frame upcalls. A new WebContent<->Compositor channel carries
display lists, scroll state, video, compositor surfaces, async
scrolling, presentation, and screenshots, with upcalls for
delegated input and compositor loss.
The helper process is a Browser-owned singleton, so Browser has to be
the source of truth for which contexts exist: it is the only party that
can register them with the helper, route backing-store and presentation
upcalls back to the right WebContent and page, and reap them when a
WebContent crashes. Move id allocation into Browser and have WebContent
ask for ids over IPC, so the runtime switch in the next commit only has
to select the backend. Behavior is preserved because Browser reproduces
the previous deterministic-vs-fresh allocation logic and the in-process
compositor still owns rendering.
Once the compositor lives in another process, the helper has to know a
context's id before any per-context message about it can be dispatched.
Today the id is minted inside CompositorHost::create_context and
returned to the caller, so it cannot be named ahead of time.
Untangle allocation from creation so Browser can mint the id and hand it
down through the call chain into both the local host and the future
remote host with no special case. The id helpers also move into a public
header so LibWeb, WebContent, and the upcoming service share one
encoding for the page-presenting bit. Behavior is preserved; the
in-process compositor still owns rendering.
The compositor is moving into a dedicated helper process. That requires
a process to launch, channels for Browser and WebContent to talk to it
over, and client proxies on each side. Land all of that as an inert
scaffold first, gated behind --enable-compositor-process, so the default
rendering path is unchanged and later commits can fill in the protocol,
the service-side state, and the runtime switch against a stable target.
Route mouse events over the compositor IPC path while async scrolling is
enabled, and let the compositor capture viewport scrollbar drags before
the main-thread event path sees them. Dragging mutates the compositor
scroll tree and schedules an async-scroll present, so the viewport thumb
and content can move without a main-thread round trip.
Keep normal main-thread event handling for misses and preserve the wheel
bypass behavior for page events.
The synchronous wheel path treats wheel deltas as CSS-pixel scroll
distances, while the async compositor scroll tree mutates scroll state
stored in device pixels. Passing the same unscaled delta into the
compositor made async scrolling advance too little whenever
device pixels per CSSPixel was greater than 1, so scrolling felt slower
than with async scrolling disabled.
Convert wheel deltas before crossing the compositor boundary and make
the compositor IPC carry only the device-pixel position and delta it
needs. This keeps AsyncScrollTree device-pixel native and makes async
viewport scrolling match the synchronous path across high-DPI displays
and page zoom levels.
Only treat a clean WebContent exit as intentional when the process no
longer has any attached views. If WebContent exits with status 0 while a
view is still attached, notify that view just like any other renderer
crash so test-web can complete the active test instead of leaving it
unresolved.
Also mark the Unix-only exit status parameter as used on Windows, where
we cannot decode a wait status.
Send the experimental UI-process wheel bypass to WebContent over the
Compositor IPC connection instead of adding a separate async scrolling
transport. This keeps bypass admission on the channel that owns bitmaps
and ready_to_paint acknowledgements.
If the compositor rejects the wheel, LibWebView falls back to regular
input delivery. If it accepts, mark the queued DOM event as having
already performed its default action so dispatch preserves ordering
without scrolling twice.
Introduce a dedicated Compositor IPC channel between the UI process and
WebContent. Use it for backing-store setup, presented bitmap delivery,
and bitmap-specific ready_to_paint acknowledgements.
This makes CompositorThread the single owner of frame presentation
bookkeeping before async scrolling starts producing frames without the
main thread.
Remove old paint and backing-store messages from WebContentClient and
PageClient so the UI process no longer observes two presentation
protocols.
Record visits as soon as a page produces useful metadata such as a
title or favicon so pages that never finish loading still become
autocomplete candidates.
Store favicons in the history schema from the start instead of
introducing an upgrade path inside this series, and cover persisted
metadata behavior in TestHistoryStore.
Route BroadcastChannel messages over IPC so matching channels can
receive them across WebContent and WebWorker processes, rather than only
within a single process.
Each channel now serializes its payload, sends it upward over IPC, and
receiving processes deliver it locally after matching by storage key and
channel name.
Generalize the backing store sharing abstraction into SharedImage, which
represents shared GPU memory independently of Skia and can be used to
share memory between different processes or different GPU contexts.
Now that LibIPC uses Mach ports for transport on macOS, IOSurface port
rights can be sent as regular IPC message attachments instead of through
a separate ad-hoc Mach message side-channel. Introduce
Web::SharedBackingStore that wraps either a MachPort (macOS) or
ShareableBitmap (other platforms) with IPC encode/decode support,
unifying backing store allocation into the existing
did_allocate_backing_stores IPC message.
These IPC methods should be expanded in the future to allow WebContent
to specify what UI elements should be kept/removed, for example, the
navigation UI.
This patch introduces a cookie cache in the WebContent process to reduce
blocking IPC calls when JS accesses document.cookie. The UI process now
maintains a cookie version counter per-domain in shared memory. When JS
reads document.cookie, we check whether we have a valid cached cookie by
comparing the current shared version to the last used version. If they
match, the cached cookie is returned without IPC.
This optimization is based on Chromium's shared versioning, in which it
was observed that 87% of document.cookie accesses were redundant. See:
https://blog.chromium.org/2024/06/introducing-shared-memory-versioning-to.html
Note that this cache only supports document.cookie, not HTTP Cookie
headers. HTTP cookies are attached to requests with varying URLs and
paths. The cookies that match the document URL might not match the
request URL, which we wouldn't know from WebContent. So attaching the
cached document cookie would be incorrect.
On https://twinings.co.uk, we see approximately 600 document.cookie
requests while the page loads. This patch reduces the time spent in
the document.cookie getter from ~45ms to 2-3ms.
These can get very large, exceeding the new IPC message size limits.
Instead of serializing them into messages (which was silly anyway)
we now send them as Core::AnonymousBuffer which uses shared memory.
Add support for WPT test variants, which allow a single test file to be
run multiple times with different URL query parameters. Tests declare
variants using `<meta name="variant" content="?param=value">` tags.
When test-web encounters a test with variants, it expands that test into
multiple runs, each with its own expectation file using the naming
convention `testname@variant.txt` (e.g., `test@run_type=uri.txt`).
Implementation details:
- WebContent observes variant meta tags and communicates them to the
test runner via a new `did_receive_test_variant_metadata` IPC call
- test-web dynamically expands tests with variants during execution,
waking idle views after each test completion to pick up new work
- Use index-based test tracking to avoid dangling references when the
test vector grows during variant expansion
- Introduce TestRunContext to group test run state, and store a static
pointer to it for signal handler access
This enables proper testing of WPT tests that use variants, such as the
html5lib parsing tests (which test uri, write, and write_single modes)
and the editing/bold tests (which split across multiple ranges).
Propagate the request initiator type (e.g., "xmlhttprequest", "fetch",
"script", "stylesheet") from LibWeb through the IPC layer to DevTools.
This enables Firefox DevTools to correctly identify XHR/fetch requests
and display appropriate cause types in the Network panel's "Initiator"
column.
This adds support for viewing request payloads (POST data) and response
bodies in the Firefox DevTools network panel.
Request bodies are captured when network requests start and passed
through IPC to the NetworkEventActor, which returns them via the
getRequestPostData protocol method.
Response bodies are streamed via a new IPC message as data is received,
accumulated in NetworkEventActor (with a 10MB size limit to prevent
memory issues), and returned via getResponseContent. Text content is
returned as UTF-8, while binary content (images, etc.) is base64.
Previously, console messages were sent using an index-based system where
DevTools would be notified of new message indices and then request them
in batches. This created synchronization issues during page navigation
when the WebContent process resets while DevTools still has stale index
state.
This changes to a push-based model where console messages are sent
immediately as resources when they are logged, matching how Firefox
DevTools handles console messages. Each message is pushed through IPC
and forwarded to DevTools as a "console-message" or "error-message"
resource.
This eliminates the need for index tracking in FrameActor and simplifies
the entire console message pipeline from WebContent through to DevTools.
