napi-sys 3.3.1

NodeJS N-API raw binding
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

// borrowed from https://github.com/neon-bindings/neon/tree/main/crates/neon/src/sys/bindings

#![allow(ambiguous_glob_reexports)]

#[cfg(any(
  target_env = "msvc",
  all(not(target_family = "wasm"), feature = "dyn-symbols")
))]
#[inline(never)]
unsafe fn load_symbol(
  host: &libloading::Library,
  name: &'static [u8],
) -> Option<*mut std::ffi::c_void> {
  match unsafe { host.get::<unsafe extern "C" fn()>(name) } {
    Ok(symbol) => unsafe { symbol.try_as_raw_ptr() },
    Err(_) => None,
  }
}

#[cfg(any(
  target_env = "msvc",
  all(not(target_family = "wasm"), feature = "dyn-symbols")
))]
macro_rules! generate {
  (@stub_fn $name:ident($($param:ident: $ptype:ty,)*) -> napi_status) => {
    unsafe extern "C" fn $name($(_: $ptype,)*) -> napi_status {
      eprintln!("Node-API symbol {} has not been loaded", stringify!($name));
      1
    }
  };
  (@stub_fn $name:ident($($param:ident: $ptype:ty,)*) -> $rtype:ty) => {
    unsafe extern "C" fn $name($(_: $ptype,)*) -> $rtype {
      eprintln!("Node-API symbol {} has not been loaded", stringify!($name));
      unsafe { std::mem::zeroed() }
    }
  };
  (@stub_fn $name:ident($($param:ident: $ptype:ty,)*)) => {
    unsafe extern "C" fn $name($(_: $ptype,)*) {
      eprintln!("Node-API symbol {} has not been loaded", stringify!($name));
    }
  };
  (extern "C" {
    $(fn $name:ident($($param:ident: $ptype:ty$(,)?)*)$( -> $rtype:ty)?;)+
  }) => {
    struct Napi {
      $(
        $name: unsafe extern "C" fn(
          $($param: $ptype,)*
        )$( -> $rtype)*,
      )*
    }

    static mut NAPI: Napi = {
      $(
        generate!(@stub_fn $name($($param: $ptype,)*) $( -> $rtype)?);
      )*

      Napi {
        $(
          $name,
        )*
      }
    };

    #[allow(clippy::missing_safety_doc)]
    pub unsafe fn load(
      host: &libloading::Library,
    ) -> Result<(), libloading::Error> {
      NAPI = Napi {
        $(
          $name: match unsafe {
            // SAFETY: every generated name identifies a Node-API function, and `setup` keeps the
            // host library alive for as long as the loaded function pointers can be called.
            $crate::load_symbol(
              host,
              concat!(stringify!($name), "\0").as_bytes(),
            )
          } {
            Some(symbol) => {
              // SAFETY: Node-API exports use the signature declared for this field. The host
              // library remains alive for as long as these function pointers can be called.
              unsafe {
                std::mem::transmute::<
                  *mut std::ffi::c_void,
                  unsafe extern "C" fn($(_: $ptype,)*)$( -> $rtype)*,
                >(symbol)
              }
            }
            // Ignore the lookup error and preserve the existing stub function.
            None => NAPI.$name,
          },
        )*
      };

      Ok(())
    }

    $(
      #[inline]
      #[allow(clippy::missing_safety_doc)]
      pub unsafe fn $name($($param: $ptype,)*)$( -> $rtype)* {
        (NAPI.$name)($($param,)*)
      }
    )*
  };
}

#[cfg(any(
  target_family = "wasm",
  all(not(target_env = "msvc"), not(feature = "dyn-symbols"))
))]
macro_rules! generate {
  (extern "C" {
    $(fn $name:ident($($param:ident: $ptype:ty$(,)?)*)$( -> $rtype:ty)?;)+
  }) => {
    extern "C" {
      $(
        pub fn $name($($param: $ptype,)*)$( -> $rtype)*;
      ) *
    }
  };
}

mod functions;
mod types;

pub use functions::*;
pub use types::*;

#[cfg(any(
  target_env = "msvc",
  all(not(target_family = "wasm"), feature = "dyn-symbols")
))]
/// Loads N-API symbols from host process.
/// Must be called at least once before using any functions in bindings or
/// they will panic
///
/// # Safety
///
/// The returned Library must be kept alive as long as any N-API
pub unsafe fn setup() -> libloading::Library {
  match load_all() {
    Err(err) => panic!("{}", err),
    Ok(l) => l,
  }
}