Module page 

Typed requests against a live page’s content.

Browser chrome turns its page actions into a PageRequest; the engine answers with exactly one WebViewEvent::PageResult carrying the same request id. Elements are addressed by the refs a prior PageRequest::Outline printed. A ref names one element of one document, so a ref from a page the tab has since left is refused rather than resolved against whatever now sits at the same position.

A page inside a frame is addressed by the frame id its parent’s outline printed ([frame=1], [frame=1.2] for a frame of a frame): a request with that id runs in the frame’s own document, and its refs and outline describe that document alone.

Structs

FrameId

A frame’s place in the page: the id its parent’s outline printed, a dot between the numbers of nested frames (2, then 2.1), at most eight deep.

PageFailure

Why a page request did nothing. code is stable, such as stale_element, obscured or unavailable.

PageKey

One key plus modifiers, written as a chord such as Enter, Shift+Tab or Control+a.

PageReply

What a completed page request observed.

PointerStep

One step of a PageRequest::Pointer gesture.

Enums

PageNavigation

Whether a page request led the page to another document, as far as the engine can tell when it answers.

PageRequest

PointerButton

PointerPoint

Where a step happens: inside an element’s box or at a viewport point.

PointerStepKind

ScrollTarget

Where a PageRequest::Scroll goes instead of a distance.

Constants

MAX_CAPTURE_BYTES

Upper bound on the pixels one capture may carry, as a PNG. What the engine paints is bounded the same way before it ever reaches this boundary.

MAX_CAPTURE_WIDTH

The widest picture a capture paints; a wider request is scaled down to it, so a picture is never larger than a person could look at.

MAX_DATA_BYTES

Upper bound on structured reply data (PageReply::data), serialised.

MAX_DRAG_STEPS

MAX_FILE_PATHS

Upper bound on the files one fill of a file input may choose.

MAX_FILE_PATH_BYTES

Upper bound on one chosen file’s path.

MAX_FILL_BYTES

Upper bound on the text one fill may insert.

MAX_FIND_NAME_BYTES

Upper bound on the accessible name a PageRequest::Find matches, as the outline prints it.

MAX_FIND_ROLE_BYTES

Upper bound on the role words a PageRequest::Find matches: a few words of the outline’s own vocabulary, never a selector.

MAX_OUTLINE_BYTES

Upper bound on an outline as it crosses the engine boundary.

MAX_PATH_POINTS

Upper bound on the points of one pointer path, and the steps of one drag, so a gesture is always a bounded amount of work for the engine.

MAX_POINTER_STEPS

Upper bound on the steps of one pointer gesture.

MAX_SCROLL_BY

How far one scroll may ask to travel in one go, CSS pixels: a wheel notch moves about 100, and a bounded distance keeps one request a bounded amount of work for the page.

MAX_SELECT_VALUES

Upper bound on the options one select may choose.

MAX_SELECT_VALUE_BYTES

Upper bound on one option value or label.

MAX_SETTLE_MS

MIN_SETTLE_QUIET_MS

Bounds of a settle wait, milliseconds.

Functions

is_element_ref

Element refs are d<document>e<element>: both parts are decimal, so a ref can never smuggle selector or script syntax to the engine.