Struct WindowMirror 

pub struct WindowMirror {

    pub label: String,
    pub kind: WindowKind,
    pub parent_label: Option<String>,
    pub opened_at: String,
    pub opened_at_ms: u64,
    pub hwnd: Option<u64>,
    pub visible: bool,
    pub iconic: bool,
    pub last_rect: Option<Rect>,
    pub last_foreground_at_ms: Option<u64>,
    pub foregrounded_since_open: bool,
    pub hidden_since_open_emitted: bool,
    pub hidden_since_open_deferred: bool,
    pub off_monitor_drift_emitted: bool,
    pub corrective_window_move_emitted: bool,
}

Phase B.4 read-only mirror of one host-owned window. The launcher learns about windows via Command::ReportWindowOpened; the host remains authoritative until B.5 flips the direction. opened_at is the launcher’s clock at the time the report arrived (RFC3339) — useful for correlating launcher logs with host logs across version skew.

Phase B.9.1 (WRR) — the observability axis (hwnd, visible, iconic, last_rect, last_foreground_at_ms, foregrounded_since_open) is populated by the host’s Win32 event hooks. Pre-B.9 these all sit at default values, which is fine: the WRR drift checks only fire when at least one of the ReportHwnd* Commands arrives, and they don’t arrive in task dev mode (no launcher → no IPC) or installed mode until the host-side hooks land. Existing reducer paths (ReportWindowOpened, ReportWindowClosed, etc.) ignore these fields entirely.

Fields

label: String

kind: WindowKind

parent_label: Option<String>

Set only for Subwindow; identifies the FullInstance that owns this window so the eventual cascade-close logic (B.5) has the parent linkage.

opened_at: String

opened_at_ms: u64

Milliseconds-since-launcher-start at which the host’s ReportWindowOpened arrived. Used by apply_hwnd_visibility_changed to suppress HiddenSinceOpen drift during the post-create placement grace window — CEF creates windows hidden, places them, then shows them, and the intermediate WM_HIDE events would otherwise fire spurious drift on every fresh window.

hwnd: Option<u64>

Phase B.9.1 — Win32 HWND linked to this label by the WRR reducer arm (via ReportHwndOpened with matching label_hint or via the post-hoc reconciliation against pending_hwnds). None until the host’s ReportHwndOpened for this label arrives.

visible: bool

Phase B.9.1 — last-known IsWindowVisible state.

iconic: bool

Phase B.9.1 — last-known minimized state.

last_rect: Option<Rect>

Phase B.9.1 — last-known window rect. None until the first ReportHwndPositionChanged arrives for the linked HWND.

last_foreground_at_ms: Option<u64>

Phase B.9.1 — milliseconds-since-launcher-start of the most recent ReportHwndForegroundChanged for this label’s HWND. None if the window has never been foregrounded.

foregrounded_since_open: bool

Phase B.9.1 — has this label been foregrounded at any point since its ReportWindowOpened? Used to fire HiddenSinceOpen drift on the first hide event when this is still false.

hidden_since_open_emitted: bool

Drift-storm fix: HiddenSinceOpen / OffMonitor / CorrectiveWindowMove each fire AT MOST ONCE per window per session. Without these caps, a fresh top-level window that goes through several SetWindowPos transitions during host placement re-emits the same event for every intermediate snapshot — observed up to 170 events in 1 second, exhausting the renderer’s V8 stack and crashing it. The cap fires once; subscribers still see the signal, no storm.

OffMonitor shares the same risk as HiddenSinceOpen because apply_hwnd_position_changed fires per WM_MOVE — dragging an already-off-monitor window emits drift on every pixel. CorrectiveWindowMove rides with it (fires per position change while !foregrounded_since_open).

All three flags are monotonic for a window’s lifetime: once true, never reset (preserve via OR-with-prior on duplicate ReportWindowOpened, codex P2 PR #708 round 3).

See docs/specs/ANALYSIS_DRIFT_STORM_RENDERER_CRASH_2026-05-06.md for storm context.

hidden_since_open_deferred: bool

Set when apply_hwnd_visibility_changed sees visible=false during the placement grace window. Marks “we suppressed a hide; if it persists past the grace, drift fires on the next reducer call via drain_deferred_hidden_since_open”. Cleared when the window subsequently becomes visible or is foregrounded. Without this, a window that goes hidden during grace and receives no further visibility events would permanently lose its HiddenSinceOpen drift signal (codex P2 PR #725 round 1).

off_monitor_drift_emitted: bool

See hidden_since_open_emitted doc above.

corrective_window_move_emitted: bool

See hidden_since_open_emitted doc above.

Trait Implementations

impl Clone for WindowMirror

fn clone(&self) -> WindowMirror

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WindowMirror

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for WindowMirror

fn eq(&self, other: &WindowMirror) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for WindowMirror

impl StructuralPartialEq for WindowMirror