pyodide_webassembly_runtime_layer/
global.rs

1use pyo3::{intern, prelude::*, sync::GILOnceCell};
2use wasm_runtime_layer::{
3    backend::{AsContext, AsContextMut, Value, WasmGlobal},
4    GlobalType,
5};
6
7use crate::{
8    conversion::{create_js_object, instanceof, ToPy, ValueExt, ValueTypeExt},
9    Engine,
10};
11
12/// A global variable accesible as an import or export in a module.
13///
14/// This type wraps a [`WebAssembly.Global`] from the JavaScript API.
15///
16/// [`WebAssembly.Global`]: https://developer.mozilla.org/en-US/docs/WebAssembly/JavaScript_interface/Global
17#[derive(Debug)]
18pub struct Global {
19    /// The global value
20    global: Py<PyAny>,
21    /// The global type
22    ty: GlobalType,
23}
24
25impl Clone for Global {
26    fn clone(&self) -> Self {
27        Python::with_gil(|py| Self {
28            global: self.global.clone_ref(py),
29            ty: self.ty,
30        })
31    }
32}
33
34impl WasmGlobal<Engine> for Global {
35    fn new(_ctx: impl AsContextMut<Engine>, value: Value<Engine>, mutable: bool) -> Self {
36        Python::with_gil(|py| -> Result<Self, PyErr> {
37            #[cfg(feature = "tracing")]
38            tracing::debug!(?value, mutable, "Global::new");
39
40            let ty = GlobalType::new(ValueExt::ty(&value), mutable);
41
42            let desc = create_js_object(py)?;
43            desc.setattr(
44                intern!(py, "value"),
45                ValueExt::ty(&value).as_js_descriptor(),
46            )?;
47            desc.setattr(intern!(py, "mutable"), mutable)?;
48
49            let value = value.to_py(py);
50
51            let global = web_assembly_global_new(py)?.call1((desc, value))?;
52
53            Ok(Self {
54                global: global.unbind(),
55                ty,
56            })
57        })
58        .expect("Global::new should not fail")
59    }
60
61    fn ty(&self, _ctx: impl AsContext<Engine>) -> GlobalType {
62        self.ty
63    }
64
65    fn set(&self, _ctx: impl AsContextMut<Engine>, new_value: Value<Engine>) -> anyhow::Result<()> {
66        if !self.ty.mutable() {
67            return Err(anyhow::anyhow!("Global is not mutable"));
68        }
69
70        Python::with_gil(|py| {
71            let global = self.global.bind(py);
72
73            #[cfg(feature = "tracing")]
74            tracing::debug!(global = %global, ?self.ty, ?new_value, "Global::set");
75
76            let new_value = new_value.to_py(py);
77
78            global.setattr(intern!(py, "value"), new_value)?;
79
80            Ok(())
81        })
82    }
83
84    fn get(&self, _ctx: impl AsContextMut<Engine>) -> Value<Engine> {
85        Python::with_gil(|py| {
86            let global = self.global.bind(py);
87
88            #[cfg(feature = "tracing")]
89            tracing::debug!(global = %global, ?self.ty, "Global::get");
90
91            let value = global.getattr(intern!(py, "value"))?;
92
93            Value::from_py_typed(value, self.ty.content())
94        })
95        .expect("Global::get should not fail")
96    }
97}
98
99impl ToPy for Global {
100    fn to_py(&self, py: Python) -> Py<PyAny> {
101        #[cfg(feature = "tracing")]
102        tracing::trace!(value = %self.global, ?self.ty, "Global::to_py");
103
104        self.global.clone_ref(py)
105    }
106}
107
108impl Global {
109    /// Creates a new global from a Python value
110    pub(crate) fn from_exported_global(
111        global: Bound<PyAny>,
112        ty: GlobalType,
113    ) -> anyhow::Result<Self> {
114        if !instanceof(&global, web_assembly_global(global.py())?)? {
115            anyhow::bail!("expected WebAssembly.Global but found {global}");
116        }
117
118        #[cfg(feature = "tracing")]
119        tracing::debug!(global = %global, ?ty, "Global::from_exported_global");
120
121        Ok(Self {
122            global: global.unbind(),
123            ty,
124        })
125    }
126}
127
128fn web_assembly_global(py: Python) -> Result<&Bound<PyAny>, PyErr> {
129    static WEB_ASSEMBLY_GLOBAL: GILOnceCell<Py<PyAny>> = GILOnceCell::new();
130    WEB_ASSEMBLY_GLOBAL.import(py, "js.WebAssembly", "Global")
131}
132
133fn web_assembly_global_new(py: Python) -> Result<&Bound<PyAny>, PyErr> {
134    static WEB_ASSEMBLY_GLOBAL_NEW: GILOnceCell<Py<PyAny>> = GILOnceCell::new();
135    WEB_ASSEMBLY_GLOBAL_NEW.import(py, "js.WebAssembly.Global", "new")
136}
pyodide_webassembly_runtime_layer/global.rs

pyodide_webassembly_runtime_layer/
global.rs
