near_sdk/types/
error.rs

1/// Enables contract runtime to panic with the given type. Any error type used in conjunction
2/// with `#[handle_result]` has to implement this trait.
3///
4/// Example:
5/// ```no_run
6/// use near_sdk::{FunctionError, near};
7///
8/// enum Error {
9///     NotFound,
10///     Unexpected { message: String },
11/// }
12///
13/// impl FunctionError for Error {
14///     fn panic(&self) -> ! {
15///         match self {
16///             Error::NotFound =>
17///                 near_sdk::env::panic_str("not found"),
18///             Error::Unexpected { message } =>
19///                 near_sdk::env::panic_str(&format!("unexpected error: {}", message))
20///         }
21///     }
22/// }
23///
24/// #[near(contract_state)]
25/// #[derive(Default)]
26/// pub struct Contract;
27///
28/// #[near]
29/// impl Contract {
30///     // if the Error does not implement FunctionError, the following will not compile with #[handle_result]
31///     #[handle_result]
32///     pub fn set(&self, value: String) -> Result<String, Error> {
33///         Err(Error::NotFound)
34///     }
35/// }
36/// ```
37pub trait FunctionError {
38    fn panic(&self) -> !;
39}
40
41impl<T> FunctionError for T
42where
43    T: AsRef<str>,
44{
45    fn panic(&self) -> ! {
46        crate::env::panic_str(self.as_ref())
47    }
48}
49
50/// A simple type used in conjunction with [FunctionError] representing that the function should
51/// abort without a custom message.
52///
53/// ```
54/// use near_sdk::{Abort, near};
55///
56/// #[near(contract_state)]
57/// #[derive(Default)]
58/// pub struct Contract;
59///
60/// #[near]
61/// impl Contract {
62///     #[handle_result]
63///     pub fn foo(&self, text: &str) -> Result<String, Abort> {
64///         if text == "success" {
65///             Ok("success".to_string())
66///         } else {
67///             Err(Abort)
68///         }
69///     }
70/// }
71/// ```
72#[derive(Debug, Clone, PartialEq, Eq)]
73pub struct Abort;
74
75impl FunctionError for Abort {
76    fn panic(&self) -> ! {
77        crate::env::abort()
78    }
79}
near_sdk/types/error.rs

near_sdk/types/
error.rs
