dovenest

dovenest/web/src/cm.rs
cm.rs
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1//! Thin, swappable bindings to the vendored CodeMirror 6 bundle.
2//!
3//! The bundle (`web/cm6.js`, built from `web/cm/wrapper.js`) installs a
4//! `window.__fbng_cm` global. This module is the *only* place that knows how
5//! to talk to it, so swapping the editor later means re-implementing just
6//! these functions.
7
8use wasm_bindgen::{JsCast, JsValue};
9
10/// A live CodeMirror editor. Destroy it with [`destroy`] when the host goes
11/// away (we do that in a Leptos `on_cleanup`).
12pub struct Cm {
13 pub view: JsValue,
14}
15
16/// Extract a human-readable message from a JS error value.
17fn err_str(e: JsValue) -> String {
18 e.clone()
19 .dyn_into::<js_sys::Error>()
20 .ok()
21 .and_then(|e| e.message().as_string())
22 .unwrap_or_else(|| "editor error".to_string())
23}
24
25fn global() -> Result<JsValue, String> {
26 let w = web_sys::window().ok_or("no window".to_string())?;
27 let wjs: JsValue = w.into();
28 let v = js_sys::Reflect::get(&wjs, &JsValue::from_str("__fbng_cm"))
29 .map_err(|e| err_str(e))?;
30 if v.is_null() || v.is_undefined() {
31 return Err("cm6 bundle not loaded".to_string());
32 }
33 Ok(v)
34}
35
36/// Call `method` on `g` with the given args.
37fn call(g: &JsValue, method: &str, args: &[&JsValue]) -> Result<JsValue, String> {
38 let m = js_sys::Reflect::get(g, &JsValue::from_str(method)).map_err(|e| err_str(e))?;
39 let f: js_sys::Function = m.unchecked_into();
40 let arr = js_sys::Array::new();
41 for a in args {
42 arr.push(a);
43 }
44 js_sys::Reflect::apply(&f, g, &arr).map_err(|e| err_str(e))
45}
46
47/// Can this file name be shown in the text editor? (Delegated to the bundle so
48/// the extension list lives in one place.)
49pub fn is_text(name: &str) -> bool {
50 global()
51 .ok()
52 .and_then(|g| call(&g, "isText", &[&JsValue::from_str(name)]).ok())
53 .and_then(|v| v.as_bool())
54 .unwrap_or(false)
55}
56
57/// Create an editor inside `container`.
58///
59/// `on_update` is an optional JS function called whenever the document changes
60/// (used to track the editor's dirty state). If provided, the caller must keep
61/// the backing `Closure` alive for as long as the editor exists.
62pub fn create(
63 container: &web_sys::Element,
64 value: &str,
65 filename: &str,
66 editable: bool,
67 on_update: Option<&JsValue>,
68) -> Result<Cm, String> {
69 let g = global()?;
70 let opts = js_sys::Object::new();
71 js_sys::Reflect::set(&opts, &JsValue::from_str("value"), &JsValue::from_str(value))
72 .map_err(|e| err_str(e))?;
73 js_sys::Reflect::set(&opts, &JsValue::from_str("filename"), &JsValue::from_str(filename))
74 .map_err(|e| err_str(e))?;
75 js_sys::Reflect::set(&opts, &JsValue::from_str("editable"), &JsValue::from_bool(editable))
76 .map_err(|e| err_str(e))?;
77 if let Some(f) = on_update {
78 js_sys::Reflect::set(&opts, &JsValue::from_str("onUpdate"), f)
79 .map_err(|e| err_str(e))?;
80 }
81
82 let view = call(
83 &g,
84 "create",
85 &[
86 &JsValue::from(container),
87 &JsValue::from(&opts),
88 ],
89 )?;
90 Ok(Cm { view })
91}
92
93pub fn destroy(view: &JsValue) {
94 let Ok(g) = global() else { return };
95 let _ = call(&g, "destroy", &[view]);
96}
97
98/// Replace the whole document (used when (re)loading a file). Used from the
99/// editor (milestone 5).
100pub fn set_value(view: &JsValue, text: &str) {
101 let Ok(g) = global() else { return };
102 let _ = call(&g, "setValue", &[view, &JsValue::from_str(text)]);
103}
104
105/// Read the current document text (used by the editor's save path, milestone
106/// 5).
107pub fn get_value(view: &JsValue) -> Option<String> {
108 let g = global().ok()?;
109 call(&g, "getValue", &[view]).ok()?.as_string()
110}
111
112/// Focus the editor (so the caret is ready for typing on open).
113pub fn focus(view: &JsValue) {
114 let Ok(g) = global() else { return };
115 let _ = call(&g, "focus", &[view]);
116}
117