piecrust_uplink/
error.rs

1// This Source Code Form is subject to the terms of the Mozilla Public
2// License, v. 2.0. If a copy of the MPL was not distributed with this
3// file, You can obtain one at http://mozilla.org/MPL/2.0/.
4//
5// Copyright (c) DUSK NETWORK. All rights reserved.
6
7extern crate alloc;
8
9use alloc::string::String;
10use core::fmt::{Display, Formatter};
11use core::str;
12
13use bytecheck::CheckBytes;
14use rkyv::{Archive, Deserialize, Serialize};
15
16/// The error possibly returned on an inter-contract-call.
17//
18// We do **not use rkyv** to pass it to the contract from the VM. Instead, we
19// use use the calling convention being able to pass negative numbers to signal
20// a failure.
21//
22// The contract writer, however, is free to pass it around and react to it if it
23// wishes.
24#[derive(Debug, Clone, PartialEq, Eq, Archive, Serialize, Deserialize)]
25#[archive_attr(derive(CheckBytes))]
26pub enum ContractError {
27    Panic(String),
28    OutOfGas,
29    DoesNotExist,
30    Unknown,
31}
32
33impl ContractError {
34    /// Returns a contract error from a return `code` and the data in the
35    /// `slice`.
36    #[cfg(feature = "abi")]
37    pub(crate) fn from_parts(code: i32, slice: &[u8]) -> Self {
38        fn get_msg(slice: &[u8]) -> String {
39            let msg_len = {
40                let mut msg_len_bytes = [0u8; 4];
41                msg_len_bytes.copy_from_slice(&slice[..4]);
42                u32::from_le_bytes(msg_len_bytes)
43            } as usize;
44
45            // SAFETY: the host guarantees that the message is valid UTF-8,
46            // so this is safe.
47            let msg = unsafe {
48                use alloc::string::ToString;
49                let msg_bytes = &slice[4..4 + msg_len];
50                let msg_str = str::from_utf8_unchecked(msg_bytes);
51                msg_str.to_string()
52            };
53
54            msg
55        }
56
57        match code {
58            -1 => Self::Panic(get_msg(slice)),
59            -2 => Self::OutOfGas,
60            -3 => Self::DoesNotExist,
61            i32::MIN => Self::Unknown,
62            _ => unreachable!("The host must guarantee that the code is valid"),
63        }
64    }
65
66    /// Write the appropriate data the `arg_buf` and return the error code.
67    pub fn to_parts(&self, slice: &mut [u8]) -> i32 {
68        fn put_msg(msg: &str, slice: &mut [u8]) {
69            let msg_bytes = msg.as_bytes();
70            let msg_len = msg_bytes.len();
71
72            let mut msg_len_bytes = [0u8; 4];
73            msg_len_bytes.copy_from_slice(&(msg_len as u32).to_le_bytes());
74
75            slice[..4].copy_from_slice(&msg_len_bytes);
76            slice[4..4 + msg_len].copy_from_slice(msg_bytes);
77        }
78
79        match self {
80            Self::Panic(msg) => {
81                put_msg(msg, slice);
82                -1
83            }
84            Self::OutOfGas => -2,
85            Self::DoesNotExist => -3,
86            Self::Unknown => i32::MIN,
87        }
88    }
89}
90
91impl From<ContractError> for i32 {
92    fn from(err: ContractError) -> Self {
93        match err {
94            ContractError::Panic(_) => -1,
95            ContractError::OutOfGas => -2,
96            ContractError::DoesNotExist => -3,
97            ContractError::Unknown => i32::MIN,
98        }
99    }
100}
101
102impl Display for ContractError {
103    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
104        match self {
105            ContractError::Panic(msg) => write!(f, "Panic: {msg}"),
106            ContractError::OutOfGas => write!(f, "OutOfGas"),
107            ContractError::DoesNotExist => {
108                write!(f, "Contract does not exist")
109            }
110            ContractError::Unknown => write!(f, "Unknown"),
111        }
112    }
113}
piecrust_uplink/error.rs

piecrust_uplink/
error.rs
