napi_h/
call_context.rs

1use std::ptr;
2
3use crate::bindgen_runtime::{FromNapiValue, TypeName};
4use crate::check_status;
5use crate::{sys, Either, Env, Error, JsUndefined, NapiValue, Result, Status};
6
7/// Function call context
8pub struct CallContext<'env> {
9  pub env: &'env mut Env,
10  raw_this: sys::napi_value,
11  callback_info: sys::napi_callback_info,
12  args: &'env [sys::napi_value],
13  /// arguments.length
14  pub length: usize,
15}
16
17impl<'env> CallContext<'env> {
18  /// The number of N-api obtained values. In practice this is the numeric
19  /// parameter provided to the `#[js_function(arg_len)]` macro.
20  ///
21  /// As a comparison, the (arguments) `.length` represents the actual number
22  /// of arguments given at a specific function call.
23  ///
24  /// If `.length < .arg_len`, then the elements in the `length .. arg_len`
25  /// range are just `JsUndefined`s.
26  ///
27  /// If `.length > .arg_len`, then truncation has happened and some args have
28  /// been lost.
29  fn arg_len(&self) -> usize {
30    self.args.len()
31  }
32
33  pub fn new(
34    env: &'env mut Env,
35    callback_info: sys::napi_callback_info,
36    raw_this: sys::napi_value,
37    args: &'env [sys::napi_value],
38    length: usize,
39  ) -> Self {
40    Self {
41      env,
42      raw_this,
43      callback_info,
44      args,
45      length,
46    }
47  }
48
49  pub fn get<ArgType: FromNapiValue>(&self, index: usize) -> Result<ArgType> {
50    if index >= self.arg_len() {
51      Err(Error::new(
52        Status::GenericFailure,
53        "Arguments index out of range".to_owned(),
54      ))
55    } else {
56      unsafe { ArgType::from_napi_value(self.env.0, self.args[index]) }
57    }
58  }
59
60  pub fn try_get<ArgType: NapiValue + TypeName + FromNapiValue>(
61    &self,
62    index: usize,
63  ) -> Result<Either<ArgType, JsUndefined>> {
64    if index >= self.arg_len() {
65      Err(Error::new(
66        Status::GenericFailure,
67        "Arguments index out of range".to_owned(),
68      ))
69    } else if index < self.length {
70      unsafe { ArgType::from_raw(self.env.0, self.args[index]) }.map(Either::A)
71    } else {
72      self.env.get_undefined().map(Either::B)
73    }
74  }
75
76  pub fn get_all(&self) -> Vec<crate::JsUnknown> {
77    /* (0 .. self.arg_len()).map(|i| self.get(i).unwrap()).collect() */
78    self
79      .args
80      .iter()
81      .map(|&raw| unsafe { crate::JsUnknown::from_raw_unchecked(self.env.0, raw) })
82      .collect()
83  }
84
85  pub fn get_new_target<V>(&self) -> Result<V>
86  where
87    V: NapiValue,
88  {
89    let mut value = ptr::null_mut();
90    check_status!(unsafe { sys::napi_get_new_target(self.env.0, self.callback_info, &mut value) })?;
91    unsafe { V::from_raw(self.env.0, value) }
92  }
93
94  pub fn this<T: NapiValue>(&self) -> Result<T> {
95    unsafe { T::from_raw(self.env.0, self.raw_this) }
96  }
97
98  pub fn this_unchecked<T: NapiValue>(&self) -> T {
99    unsafe { T::from_raw_unchecked(self.env.0, self.raw_this) }
100  }
101}
napi_h/call_context.rs

napi_h/
call_context.rs
