wry_bindgen/
function.rs

1//! JavaScript function references and Rust callback management.
2//!
3//! This module provides types for calling JavaScript functions from Rust
4//! and for registering Rust callbacks that can be called from JavaScript.
5
6// Allow clippy lints for macro-generated code and internal types
7#![allow(clippy::too_many_arguments)]
8#![allow(clippy::type_complexity)]
9
10use alloc::vec::Vec;
11use core::cell::RefCell;
12use core::marker::PhantomData;
13
14use crate::batch::{force_flush, run_js_sync, with_runtime};
15use crate::encode::{BatchableResult, BinaryEncode, EncodeTypeDef, TYPE_CACHED, TYPE_FULL};
16use crate::ipc::DecodedData;
17use crate::ipc::EncodedData;
18
19/// Reserved function ID for dropping native Rust refs when JS objects are GC'd.
20/// JS sends this when a FinalizationRegistry callback fires for a RustFunction.
21pub const DROP_NATIVE_REF_FN_ID: u32 = 0xFFFFFFFF;
22
23/// Reserved function ID for calling exported Rust struct methods from JS.
24/// JS sends this with the export name to call the appropriate handler.
25pub const CALL_EXPORT_FN_ID: u32 = 0xFFFFFFFE;
26
27/// Encode type definitions for a function call.
28/// On first call for a type signature, sends TYPE_FULL + id + param_count + type defs.
29/// On subsequent calls, sends TYPE_CACHED + id.
30fn encode_function_types(encoder: &mut EncodedData, encode_types: impl FnOnce(&mut Vec<u8>)) {
31    // Always encode type definitions to get the bytes
32    let mut type_buf = Vec::new();
33    encode_types(&mut type_buf);
34
35    with_runtime(|state| {
36        let (id, is_cached) = state.get_or_create_type_id(type_buf.clone());
37        if is_cached {
38            // Cached - just send marker + ID
39            encoder.push_u8(TYPE_CACHED);
40            encoder.push_u32(id);
41        } else {
42            // First time - send full type def + ID
43            encoder.push_u8(TYPE_FULL);
44            encoder.push_u32(id);
45
46            // Push the type definition bytes
47            for byte in type_buf {
48                encoder.push_u8(byte);
49            }
50        }
51    });
52}
53
54/// A reference to a JavaScript function that can be called from Rust.
55///
56/// The type parameter encodes the function signature.
57/// Arguments and return values are serialized using the binary protocol.
58pub struct JSFunction<T> {
59    id: u32,
60    function: PhantomData<T>,
61}
62
63impl<T> JSFunction<T> {
64    pub const fn new(id: u32) -> Self {
65        Self {
66            id,
67            function: PhantomData,
68        }
69    }
70
71    /// Get the function ID.
72    pub fn id(&self) -> u32 {
73        self.id
74    }
75}
76
77macro_rules! impl_js_function_call {
78    // Base case: zero arguments
79    (0,) => {
80        impl<R: BatchableResult + EncodeTypeDef> JSFunction<fn() -> R> {
81            pub fn call(&self) -> R {
82                run_js_sync::<R>(self.id, |encoder| {
83                    encode_function_types(encoder, |buf| {
84                        buf.push(0);
85                        R::encode_type_def(buf);
86                    });
87                })
88            }
89        }
90    };
91    // Recursive case: N arguments
92    ($n:expr, $($T:ident $P:ident $arg:ident),+) => {
93        impl<$($T: EncodeTypeDef,)+ R: BatchableResult + EncodeTypeDef>
94            JSFunction<fn($($T),+) -> R>
95        {
96            pub fn call<$($P),+>(&self, $($arg: $T),+) -> R
97            where
98                $($T: BinaryEncode<$P>,)+
99            {
100                run_js_sync::<R>(self.id, |encoder| {
101                    encode_function_types(encoder, |buf| {
102                        buf.push($n);
103                        $($T::encode_type_def(buf);)+
104                        R::encode_type_def(buf);
105                    });
106                    $($arg.encode(encoder);)+
107                })
108            }
109        }
110    };
111}
112
113impl_js_function_call!(0,);
114impl_js_function_call!(1, T1 P1 arg1);
115impl_js_function_call!(2, T1 P1 arg1, T2 P2 arg2);
116impl_js_function_call!(3, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3);
117impl_js_function_call!(4, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4);
118impl_js_function_call!(5, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5);
119impl_js_function_call!(6, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6);
120impl_js_function_call!(7, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7);
121impl_js_function_call!(8, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8);
122impl_js_function_call!(9, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9);
123impl_js_function_call!(10, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10);
124impl_js_function_call!(11, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11);
125impl_js_function_call!(12, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12);
126impl_js_function_call!(13, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13);
127impl_js_function_call!(14, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14);
128impl_js_function_call!(15, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15);
129impl_js_function_call!(16, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16);
130impl_js_function_call!(17, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17);
131impl_js_function_call!(18, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18);
132impl_js_function_call!(19, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19);
133impl_js_function_call!(20, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20);
134impl_js_function_call!(21, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21);
135impl_js_function_call!(22, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22);
136impl_js_function_call!(23, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23);
137impl_js_function_call!(24, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24);
138impl_js_function_call!(25, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25);
139impl_js_function_call!(26, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26);
140impl_js_function_call!(27, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26, T27 P27 arg27);
141impl_js_function_call!(28, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26, T27 P27 arg27, T28 P28 arg28);
142impl_js_function_call!(29, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26, T27 P27 arg27, T28 P28 arg28, T29 P29 arg29);
143impl_js_function_call!(30, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26, T27 P27 arg27, T28 P28 arg28, T29 P29 arg29, T30 P30 arg30);
144impl_js_function_call!(31, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26, T27 P27 arg27, T28 P28 arg28, T29 P29 arg29, T30 P30 arg30, T31 P31 arg31);
145impl_js_function_call!(32, T1 P1 arg1, T2 P2 arg2, T3 P3 arg3, T4 P4 arg4, T5 P5 arg5, T6 P6 arg6, T7 P7 arg7, T8 P8 arg8, T9 P9 arg9, T10 P10 arg10, T11 P11 arg11, T12 P12 arg12, T13 P13 arg13, T14 P14 arg14, T15 P15 arg15, T16 P16 arg16, T17 P17 arg17, T18 P18 arg18, T19 P19 arg19, T20 P20 arg20, T21 P21 arg21, T22 P22 arg22, T23 P23 arg23, T24 P24 arg24, T25 P25 arg25, T26 P26 arg26, T27 P27 arg27, T28 P28 arg28, T29 P29 arg29, T30 P30 arg30, T31 P31 arg31, T32 P32 arg32);
146
147/// Internal type for storing Rust callback functions.
148/// Always stores as `Rc<dyn Fn(...)>` for uniform handling.
149/// - For `Fn` closures: stored directly, supports reentrant calls
150/// - For `FnMut` closures: wrapped in RefCell internally, panics on reentrant calls
151pub(crate) struct RustCallback {
152    f: alloc::rc::Rc<dyn Fn(&mut DecodedData, &mut EncodedData)>,
153}
154
155impl RustCallback {
156    /// Create a callback from an `Fn` closure (supports reentrant calls)
157    pub fn new_fn<F>(f: F) -> Self
158    where
159        F: Fn(&mut DecodedData, &mut EncodedData) + 'static,
160    {
161        Self {
162            f: alloc::rc::Rc::new(move |data: &mut DecodedData, encoder: &mut EncodedData| {
163                f(data, encoder);
164                force_flush();
165            }),
166        }
167    }
168
169    /// Create a callback from an `FnMut` closure (panics on reentrant calls)
170    pub fn new_fn_mut<F>(f: F) -> Self
171    where
172        F: FnMut(&mut DecodedData, &mut EncodedData) + 'static,
173    {
174        // Wrap the FnMut in a RefCell, then create an Fn wrapper
175        let cell = RefCell::new(f);
176        Self {
177            f: alloc::rc::Rc::new(move |data: &mut DecodedData, encoder: &mut EncodedData| {
178                {
179                    let mut f = cell.borrow_mut();
180                    f(data, encoder);
181                }
182                force_flush();
183            }),
184        }
185    }
186
187    /// Get a cloned Rc to the callback
188    pub fn clone_rc(&self) -> alloc::rc::Rc<dyn Fn(&mut DecodedData, &mut EncodedData)> {
189        self.f.clone()
190    }
191}
wry_bindgen/function.rs

wry_bindgen/
function.rs
