linera_wasmer_vm/trap/
trap.rs

1use backtrace::Backtrace;
2use std::error::Error;
3use std::fmt;
4use wasmer_types::TrapCode;
5
6/// Stores trace message with backtrace.
7#[derive(Debug)]
8pub enum Trap {
9    /// A user-raised trap through `raise_user_trap`.
10    User(Box<dyn Error + Send + Sync>),
11
12    /// A trap raised from the Wasm generated code
13    ///
14    /// Note: this trap is deterministic (assuming a deterministic host implementation)
15    Wasm {
16        /// The program counter in generated code where this trap happened.
17        pc: usize,
18        /// Native stack backtrace at the time the trap occurred
19        backtrace: Backtrace,
20        /// Optional trapcode associated to the signal that caused the trap
21        signal_trap: Option<TrapCode>,
22    },
23
24    /// A trap raised from a wasm libcall
25    ///
26    /// Note: this trap is deterministic (assuming a deterministic host implementation)
27    Lib {
28        /// Code of the trap.
29        trap_code: TrapCode,
30        /// Native stack backtrace at the time the trap occurred
31        backtrace: Backtrace,
32    },
33
34    /// A trap indicating that the runtime was unable to allocate sufficient memory.
35    ///
36    /// Note: this trap is nondeterministic, since it depends on the host system.
37    OOM {
38        /// Native stack backtrace at the time the OOM occurred
39        backtrace: Backtrace,
40    },
41}
42
43fn _assert_trap_is_sync_and_send(t: &Trap) -> (&dyn Sync, &dyn Send) {
44    (t, t)
45}
46
47impl Trap {
48    /// Construct a new Error with the given a user error.
49    ///
50    /// Internally saves a backtrace when constructed.
51    pub fn user(err: Box<dyn Error + Send + Sync>) -> Self {
52        Self::User(err)
53    }
54
55    /// Construct a new Wasm trap with the given source location and backtrace.
56    ///
57    /// Internally saves a backtrace when constructed.
58    pub fn wasm(pc: usize, backtrace: Backtrace, signal_trap: Option<TrapCode>) -> Self {
59        Self::Wasm {
60            pc,
61            backtrace,
62            signal_trap,
63        }
64    }
65
66    /// Returns trap code, if it's a Trap
67    pub fn to_trap(self) -> Option<TrapCode> {
68        unimplemented!()
69    }
70
71    /// Construct a new Wasm trap with the given trap code.
72    pub fn lib(trap_code: TrapCode) -> Self {
73        let backtrace = Backtrace::from(vec![]);
74        Self::Lib {
75            trap_code,
76            backtrace,
77        }
78    }
79
80    /// Construct a new OOM trap with the given source location and trap code.
81    pub fn oom() -> Self {
82        let backtrace = Backtrace::from(vec![]);
83        Self::OOM { backtrace }
84    }
85
86    /// Attempts to downcast the `Trap` to a concrete type.
87    pub fn downcast<T: Error + 'static>(self) -> Result<T, Self> {
88        match self {
89            // We only try to downcast user errors
90            Self::User(err) if err.is::<T>() => Ok(*err.downcast::<T>().unwrap()),
91            _ => Err(self),
92        }
93    }
94
95    /// Attempts to downcast the `Trap` to a concrete type.
96    pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> {
97        match &self {
98            // We only try to downcast user errors
99            Self::User(err) if err.is::<T>() => err.downcast_ref::<T>(),
100            _ => None,
101        }
102    }
103
104    /// Returns true if the `Trap` is the same as T
105    pub fn is<T: Error + 'static>(&self) -> bool {
106        match self {
107            Self::User(err) => err.is::<T>(),
108            _ => false,
109        }
110    }
111}
112
113impl std::error::Error for Trap {
114    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
115        match &self {
116            Self::User(err) => Some(&**err),
117            _ => None,
118        }
119    }
120}
121
122impl fmt::Display for Trap {
123    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
124        match self {
125            Self::User(e) => write!(f, "{}", e),
126            Self::Lib { .. } => write!(f, "lib"),
127            Self::Wasm { .. } => write!(f, "wasm"),
128            Self::OOM { .. } => write!(f, "Wasmer VM out of memory"),
129        }
130    }
131}
linera_wasmer_vm/trap/trap.rs

linera_wasmer_vm/trap/
trap.rs
