pmacs/src/semantic_client.rs

535 lines
19 KiB
Rust

// semantic_client.rs --- Headless consumer of the SemanticFrame wire (T M11.5).
//! The frontend↔instance glue for the semantic projection.
//!
//! `docs/semantic-frontend-protocol.md` deliberately moves rendering
//! correctness (shaping, wrap, hit-testing) into a GPU frontend the
//! instance test harness cannot exercise, and bounds the *testable*
//! surface to "the frontend↔instance glue, not all rendering."
//! `SemanticClient` is exactly that glue, made headless and
//! self-contained: no terminal, no GPU, no pixels.
//!
//! It composes the two replica layers a `semantic_render` session
//! needs:
//!
//! - [`BufferMirror`] — the rope replica (M10.10). The semantic frame
//! ships *no text*; the client holds the document locally via
//! `BufferSnapshot` + `CrdtOp`, exactly as the grid TUI does.
//! - A [`SemanticModel`] per family — the *interpretation* layer:
//! byte-anchored styling / decorations, reconstructed from the
//! `full` + dirty-segment deltas (M11.4).
//!
//! The client also produces the one frontend→instance message the
//! protocol adds — [`FrontendEvent::Viewport`] — declaring the byte
//! range it has "on screen" so the instance scopes its projection.
//!
//! Read-back accessors (`text`, `effective_style_at`,
//! `decoration_kinds_at`) exist so a test can assert the
//! reconstruction equals the instance's intent — the
//! "reconstruction-equivalence" golden discipline (no snapshot crate;
//! matches the repo's explicit-assertion style).
use std::collections::HashMap;
use crate::buffer::BufferId;
use crate::buffer_mirror::BufferMirror;
use crate::cell::Style;
use crate::overlay::merge_styles;
use crate::protocol::{
ByteRange, Decoration, DecorationKind, DecorationSegment, FrontendEvent, FrontendId,
InstanceMessage, StyleSegment, StyleSpan,
};
/// An item the model can restrict to a sub-range. `range` is where it
/// applies; `clipped` is the item narrowed to `bounds` (or `None`
/// when disjoint). The semantic frame's items are byte-anchored, so
/// both families implement this uniformly.
trait Clip: Clone {
fn range(&self) -> ByteRange;
fn clipped(&self, bounds: ByteRange) -> Option<Self>;
}
fn intersect(a: ByteRange, b: ByteRange) -> Option<ByteRange> {
let start = a.start.max(b.start);
let end = a.end.min(b.end);
(end > start).then_some(ByteRange { start, end })
}
impl Clip for StyleSpan {
fn range(&self) -> ByteRange {
self.range
}
fn clipped(&self, bounds: ByteRange) -> Option<Self> {
intersect(self.range, bounds).map(|range| Self {
range,
style: self.style,
})
}
}
impl Clip for Decoration {
fn range(&self) -> ByteRange {
self.range
}
fn clipped(&self, bounds: ByteRange) -> Option<Self> {
intersect(self.range, bounds).map(|range| Self {
range,
kind: self.kind,
})
}
}
/// One reconstructed dirty region. The M11.4 contract — *each segment
/// carries every current item intersecting its range* — makes a tile
/// self-contained: rendering any byte in `range` consults only this
/// tile's `items`, never a neighbour's. That is what lets incremental
/// application be a clean per-tile replacement instead of fragile
/// cross-span surgery.
#[derive(Clone, Debug, Eq, PartialEq)]
struct Tile<T> {
range: ByteRange,
items: Vec<T>,
}
/// One family's reconstructed view of one buffer: disjoint tiles
/// ordered by start. Bytes covered by no tile have no styling /
/// decoration (default), exactly as the instance intends for regions
/// outside the declared viewport.
struct SemanticModel<T> {
tiles: Vec<Tile<T>>,
}
// Manual `Default` — the derive would wrongly require `T: Default`
// (a `StyleSpan`/`Decoration` has no meaningful default); an empty
// model is just no tiles regardless of `T`.
impl<T> Default for SemanticModel<T> {
fn default() -> Self {
Self { tiles: Vec::new() }
}
}
impl<T: Clip> SemanticModel<T> {
/// Apply one frame. `full` discards everything first (resync);
/// otherwise each segment replaces only its own byte range —
/// tiles straddling a segment are split, keeping the parts
/// outside it (clipped), and the segment's items become the new
/// tile for the region.
fn apply(&mut self, full: bool, segments: &[(ByteRange, Vec<T>)]) {
if full {
self.tiles = segments
.iter()
.map(|(range, items)| Tile {
range: *range,
items: items.clone(),
})
.collect();
} else {
for (range, items) in segments {
self.replace_region(*range, items.clone());
}
}
self.tiles.sort_by_key(|t| (t.range.start, t.range.end));
}
fn replace_region(&mut self, region: ByteRange, items: Vec<T>) {
let mut next: Vec<Tile<T>> = Vec::with_capacity(self.tiles.len() + 1);
for t in std::mem::take(&mut self.tiles) {
if intersect(t.range, region).is_none() {
next.push(t);
continue;
}
// Keep the parts of `t` outside `region`, each carrying
// only the items that survive the narrower range.
if t.range.start < region.start {
let left = ByteRange {
start: t.range.start,
end: region.start,
};
next.push(Tile {
range: left,
items: t.items.iter().filter_map(|i| i.clipped(left)).collect(),
});
}
if t.range.end > region.end {
let right = ByteRange {
start: region.end,
end: t.range.end,
};
next.push(Tile {
range: right,
items: t.items.iter().filter_map(|i| i.clipped(right)).collect(),
});
}
// The overlapped middle is dropped — `items` re-supplies it.
}
next.push(Tile {
range: region,
items,
});
self.tiles = next;
}
/// Items covering `byte`, in instance order (the order they were
/// shipped — wider-first for styling, so a fold via
/// [`merge_styles`] reproduces the grid path's layering).
fn items_at(&self, byte: u64) -> impl Iterator<Item = &T> {
self.tiles
.iter()
.find(|t| t.range.start <= byte && byte < t.range.end)
.into_iter()
.flat_map(move |t| {
t.items
.iter()
.filter(move |i| i.range().start <= byte && byte < i.range().end)
})
}
fn tile_ranges(&self) -> Vec<ByteRange> {
self.tiles.iter().map(|t| t.range).collect()
}
}
/// A headless `semantic_render` session: rope replica + the styling
/// and decoration interpretation layers, plus the `Viewport` event it
/// emits. Drive it by feeding every [`InstanceMessage`] through
/// [`Self::apply`]; read it back through the accessors.
pub struct SemanticClient {
frontend_id: FrontendId,
mirror: BufferMirror,
styles: HashMap<BufferId, SemanticModel<StyleSpan>>,
decos: HashMap<BufferId, SemanticModel<Decoration>>,
}
impl SemanticClient {
/// Construct a client for the session assigned `frontend_id`
/// (the id the daemon stamped in `Hello`).
#[must_use]
pub fn new(frontend_id: FrontendId) -> Self {
Self {
frontend_id,
mirror: BufferMirror::new(frontend_id),
styles: HashMap::new(),
decos: HashMap::new(),
}
}
/// The session's assigned frontend id.
#[must_use]
pub fn frontend_id(&self) -> FrontendId {
self.frontend_id
}
/// Build the [`FrontendEvent::Viewport`] declaring `visible` for
/// `buffer_id`. The caller writes it to the daemon; the instance
/// scopes its projection to this range. `generation` is the CRDT
/// version the frontend computed the range against (M11.4 records
/// it for the future viewport-race refinement).
#[must_use]
pub fn viewport_event(
&self,
buffer_id: BufferId,
visible: ByteRange,
generation: u64,
) -> FrontendEvent {
FrontendEvent::Viewport {
frontend_id: self.frontend_id,
buffer_id,
visible,
generation,
}
}
/// Route one instance message into the replica/interpretation
/// layers. Unrelated variants (grid `CellDelta`/`Cursor`,
/// presence, and the not-yet-produced adornment/fold/resource
/// families) are ignored — a semantic session lays out locally
/// and never consumes the grid projection.
pub fn apply(&mut self, msg: &InstanceMessage) {
match msg {
InstanceMessage::BufferSnapshot {
buffer_id,
crdt_snapshot,
} => {
// `AlreadyInitialized` means a duplicate bootstrap for
// a buffer we already mirror — benign for a consumer.
let _ = self.mirror.init_from_snapshot(*buffer_id, crdt_snapshot);
}
InstanceMessage::CrdtOp { buffer_id, op } => {
// A pure consumer never edits, so it is never the
// op's source — no echo to filter (the daemon also
// excludes the sender). Drop a non-applying op
// silently, as the test Observer does.
let _ = self.mirror.apply_remote_op(*buffer_id, &op.bytes);
}
InstanceMessage::CursorByte {
buffer_id,
byte_pos,
} => {
self.mirror
.set_cursor_byte_pos(*buffer_id, *byte_pos as usize);
}
InstanceMessage::StyleSpans {
buffer_id,
full,
segments,
..
} => {
let segs: Vec<(ByteRange, Vec<StyleSpan>)> = segments
.iter()
.map(|s: &StyleSegment| (s.range, s.spans.clone()))
.collect();
self.styles
.entry(*buffer_id)
.or_default()
.apply(*full, &segs);
}
InstanceMessage::Decorations {
buffer_id,
full,
segments,
..
} => {
let segs: Vec<(ByteRange, Vec<Decoration>)> = segments
.iter()
.map(|s: &DecorationSegment| (s.range, s.decorations.clone()))
.collect();
self.decos
.entry(*buffer_id)
.or_default()
.apply(*full, &segs);
}
// Grid projection, presence, and the honest-stub families
// (InlineAdornments / BlockAdornments / FoldState /
// ResourceOffer) — a semantic session does not consume
// these. ModeLine / Signal / Goodbye are session control,
// handled by the attach loop, not the model.
_ => {}
}
}
/// The reconstructed document text for `buffer_id` (the rope
/// replica materialized), or `None` if not yet bootstrapped.
#[must_use]
pub fn text(&self, buffer_id: BufferId) -> Option<String> {
self.mirror.materialize(buffer_id)
}
/// Whether the rope replica for `buffer_id` has been bootstrapped.
#[must_use]
pub fn is_ready(&self, buffer_id: BufferId) -> bool {
self.mirror.is_ready(buffer_id)
}
/// The cursor byte position the instance last reported.
#[must_use]
pub fn cursor_byte_pos(&self, buffer_id: BufferId) -> Option<usize> {
self.mirror.cursor_byte_pos(buffer_id)
}
/// The effective style at `byte`: every reconstructed span
/// covering it, folded via [`merge_styles`] in instance order.
/// `Style::default()` when nothing covers it (outside the
/// declared viewport, or no styling there).
#[must_use]
pub fn effective_style_at(&self, buffer_id: BufferId, byte: u64) -> Style {
self.styles
.get(&buffer_id)
.map_or_else(Style::default, |m| {
m.items_at(byte)
.fold(Style::default(), |acc, s| merge_styles(acc, s.style))
})
}
/// The decoration kinds covering `byte`, in instance order
/// (duplicates preserved — a byte can carry, e.g., both a
/// selection and a diagnostic).
#[must_use]
pub fn decoration_kinds_at(&self, buffer_id: BufferId, byte: u64) -> Vec<DecorationKind> {
self.decos
.get(&buffer_id)
.map_or_else(Vec::new, |m| m.items_at(byte).map(|d| d.kind).collect())
}
/// Reconstructed styling tile ranges for `buffer_id` — for
/// invariant assertions (disjointness, in-viewport bounds).
#[must_use]
pub fn style_tile_ranges(&self, buffer_id: BufferId) -> Vec<ByteRange> {
self.styles
.get(&buffer_id)
.map(SemanticModel::tile_ranges)
.unwrap_or_default()
}
/// Reconstructed decoration tile ranges for `buffer_id`.
#[must_use]
pub fn decoration_tile_ranges(&self, buffer_id: BufferId) -> Vec<ByteRange> {
self.decos
.get(&buffer_id)
.map(SemanticModel::tile_ranges)
.unwrap_or_default()
}
}
#[cfg(test)]
mod tests {
use super::*;
fn br(start: u64, end: u64) -> ByteRange {
ByteRange { start, end }
}
fn styled(fg_bold: bool) -> Style {
Style {
bold: fg_bold,
..Style::default()
}
}
fn span(start: u64, end: u64, bold: bool) -> StyleSpan {
StyleSpan {
range: br(start, end),
style: styled(bold),
}
}
fn deco(start: u64, end: u64, kind: DecorationKind) -> Decoration {
Decoration {
range: br(start, end),
kind,
}
}
#[test]
fn full_frame_replaces_the_whole_model() {
let mut m: SemanticModel<StyleSpan> = SemanticModel::default();
m.apply(true, &[(br(0, 10), vec![span(2, 5, true)])]);
assert_eq!(m.tile_ranges(), vec![br(0, 10)]);
// A second full frame discards the first entirely.
m.apply(true, &[(br(0, 4), vec![span(0, 4, false)])]);
assert_eq!(m.tile_ranges(), vec![br(0, 4)]);
assert_eq!(m.items_at(2).count(), 1);
assert!(m.items_at(8).next().is_none(), "byte 8 no longer covered");
}
#[test]
fn incremental_segment_splits_a_straddling_tile_and_keeps_the_edges() {
let mut m: SemanticModel<StyleSpan> = SemanticModel::default();
// One wide tile spanning [0,30) with a span over [0,30).
m.apply(true, &[(br(0, 30), vec![span(0, 30, true)])]);
// A dirty segment repaints the middle [10,20).
m.apply(false, &[(br(10, 20), vec![span(10, 20, false)])]);
// Edges [0,10) and [20,30) survive (clipped), middle replaced.
assert_eq!(
m.tile_ranges(),
vec![br(0, 10), br(10, 20), br(20, 30)],
"straddling tile split into left edge / new middle / right edge"
);
// Edge styling preserved (bold); middle replaced (not bold).
assert!(m.items_at(5).next().unwrap().style.bold);
assert!(!m.items_at(15).next().unwrap().style.bold);
assert!(m.items_at(25).next().unwrap().style.bold);
}
#[test]
fn bytes_outside_all_tiles_have_default_style() {
let c = SemanticClient::new(FrontendId(7));
let b = BufferId::next();
assert_eq!(c.effective_style_at(b, 3), Style::default());
assert!(c.decoration_kinds_at(b, 3).is_empty());
}
#[test]
fn overlapping_spans_fold_in_order_via_merge_styles() {
let mut m: SemanticModel<StyleSpan> = SemanticModel::default();
// Wider span (bold) then a nested non-bold span — instance
// ships wider-first; merge_styles overlays in that order.
let wide = StyleSpan {
range: br(0, 10),
style: Style {
bold: true,
..Style::default()
},
};
let inner = StyleSpan {
range: br(4, 6),
style: Style {
italic: true,
..Style::default()
},
};
m.apply(true, &[(br(0, 10), vec![wide, inner])]);
let folded = m
.items_at(5)
.fold(Style::default(), |acc, s| merge_styles(acc, s.style));
assert!(folded.bold && folded.italic, "both layers apply at byte 5");
let only_wide = m
.items_at(1)
.fold(Style::default(), |acc, s| merge_styles(acc, s.style));
assert!(only_wide.bold && !only_wide.italic);
}
#[test]
fn decoration_model_tracks_kinds_at_byte() {
let mut m: SemanticModel<Decoration> = SemanticModel::default();
m.apply(
true,
&[(
br(0, 20),
vec![
deco(2, 8, DecorationKind::Selection),
deco(5, 6, DecorationKind::DiagnosticError),
],
)],
);
let at5: Vec<_> = m.items_at(5).map(|d| d.kind).collect();
assert_eq!(
at5,
vec![DecorationKind::Selection, DecorationKind::DiagnosticError]
);
assert_eq!(
m.items_at(3).map(|d| d.kind).collect::<Vec<_>>(),
vec![DecorationKind::Selection]
);
assert!(m.items_at(15).next().is_none());
}
#[test]
fn client_ignores_grid_and_stub_families() {
let mut c = SemanticClient::new(FrontendId(2));
let b = BufferId::next();
// None of these should panic or affect the model.
c.apply(&InstanceMessage::Cursor(None));
c.apply(&InstanceMessage::FoldState {
buffer_id: b,
folds: vec![br(0, 1)],
});
c.apply(&InstanceMessage::ResourceOffer {
handle: 1,
mime: "image/png".into(),
body: crate::protocol::ResourceBody::Inline(vec![1, 2]),
});
assert!(c.style_tile_ranges(b).is_empty());
assert!(c.text(b).is_none());
}
#[test]
fn viewport_event_carries_the_sessions_fid() {
let c = SemanticClient::new(FrontendId(9));
let b = BufferId::next();
match c.viewport_event(b, br(0, 64), 3) {
FrontendEvent::Viewport {
frontend_id,
buffer_id,
visible,
generation,
} => {
assert_eq!(frontend_id, FrontendId(9));
assert_eq!(buffer_id, b);
assert_eq!(visible, br(0, 64));
assert_eq!(generation, 3);
}
other => panic!("expected Viewport, got {other:?}"),
}
}
}