text_document/
events.rs

1//! Document event types and subscription handle.
2
3use std::sync::Arc;
4use std::sync::atomic::AtomicBool;
5
6use crate::inner::{CallbackEntry, TextDocumentInner};
7
8/// Events emitted by a [`TextDocument`](crate::TextDocument).
9///
10/// Subscribe via [`TextDocument::on_change`](crate::TextDocument::on_change) (callback-based)
11/// or poll via [`TextDocument::poll_events`](crate::TextDocument::poll_events) (frame-loop).
12///
13/// These events carry enough information for a UI to do incremental updates —
14/// repaint only the affected region, not the entire document.
15#[derive(Debug, Clone, PartialEq)]
16pub enum DocumentEvent {
17    /// Text content changed at a specific region.
18    ///
19    /// Emitted by: `insert_text`, `delete_char`, `delete_previous_char`,
20    /// `remove_selected_text`, `insert_formatted_text`, `insert_block`,
21    /// `insert_html`, `insert_markdown`, `insert_fragment`, `insert_image`.
22    ContentsChanged {
23        position: usize,
24        chars_removed: usize,
25        chars_added: usize,
26        blocks_affected: usize,
27    },
28
29    /// Formatting changed without text content change.
30    FormatChanged {
31        position: usize,
32        length: usize,
33        /// Distinguishes block-level changes (relayout needed) from
34        /// character-level changes (reshaping only).
35        kind: crate::flow::FormatChangeKind,
36    },
37
38    /// Only paint-level highlight attributes changed (colors, underline
39    /// decorations) on a paint-only highlighter. The shaping input
40    /// (`fragments`) is unchanged, so the layout engine can recolor the
41    /// cached layout without reshaping or reflowing.
42    ///
43    /// `position` / `length` are document-absolute character offsets. For
44    /// whole-document rehighlights both are 0; for single-block
45    /// rehighlights they bound the affected block.
46    HighlightPaintChanged { position: usize, length: usize },
47
48    /// Block count changed. Carries the new count.
49    BlockCountChanged(usize),
50
51    /// Flow elements were inserted at the given index in the main
52    /// frame's `child_order`.
53    ///
54    /// This is a performance optimization — the layout engine can
55    /// update incrementally instead of re-querying
56    /// [`TextDocument::flow()`](crate::TextDocument::flow).
57    FlowElementsInserted { flow_index: usize, count: usize },
58
59    /// Flow elements were removed starting at the given index in the
60    /// main frame's `child_order`.
61    FlowElementsRemoved { flow_index: usize, count: usize },
62
63    /// The document was completely replaced (import, clear).
64    DocumentReset,
65
66    /// Undo/redo was performed or availability changed.
67    UndoRedoChanged { can_undo: bool, can_redo: bool },
68
69    /// The modified flag changed.
70    ModificationChanged(bool),
71
72    /// A long operation progressed.
73    LongOperationProgress {
74        operation_id: String,
75        percent: f64,
76        message: String,
77    },
78
79    /// A long operation completed or failed.
80    LongOperationFinished {
81        operation_id: String,
82        success: bool,
83        error: Option<String>,
84    },
85}
86
87/// Handle to a document event subscription.
88///
89/// Events are delivered as long as this handle is alive.
90/// Drop it to unsubscribe. No explicit unsubscribe method needed.
91pub struct Subscription {
92    alive: Arc<AtomicBool>,
93}
94
95impl Drop for Subscription {
96    fn drop(&mut self) {
97        self.alive
98            .store(false, std::sync::atomic::Ordering::Relaxed);
99    }
100}
101
102/// Register a callback with the document inner, returning a Subscription handle.
103pub(crate) fn subscribe_inner<F>(inner: &mut TextDocumentInner, callback: F) -> Subscription
104where
105    F: Fn(DocumentEvent) + Send + Sync + 'static,
106{
107    let alive = Arc::new(AtomicBool::new(true));
108    inner.callbacks.push(CallbackEntry {
109        alive: Arc::downgrade(&alive),
110        callback: Arc::new(callback),
111    });
112    Subscription { alive }
113}
text_document/events.rs

text_document/
events.rs
