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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
//! The WebAssembly possible errors
use crate::{ExternType, Pages};
use std::io;
use thiserror::Error;

/// The Serialize error can occur when serializing a
/// compiled Module into a binary.
#[derive(Error, Debug)]
pub enum SerializeError {
    /// An IO error
    #[error(transparent)]
    Io(#[from] io::Error),
    /// A generic serialization error
    #[error("{0}")]
    Generic(String),
}

/// The Deserialize error can occur when loading a
/// compiled Module from a binary.
#[derive(Error, Debug)]
pub enum DeserializeError {
    /// An IO error
    #[error(transparent)]
    Io(#[from] io::Error),
    /// A generic deserialization error
    #[error("{0}")]
    Generic(String),
    /// Incompatible serialized binary
    #[error("incompatible binary: {0}")]
    Incompatible(String),
    /// The provided binary is corrupted
    #[error("corrupted binary: {0}")]
    CorruptedBinary(String),
    /// The binary was valid, but we got an error when
    /// trying to allocate the required resources.
    #[error(transparent)]
    Compiler(#[from] CompileError),
    /// Input artifact bytes have an invalid length
    #[error("invalid input bytes: expected {expected} bytes, got {got}")]
    InvalidByteLength {
        /// How many bytes were expected
        expected: usize,
        /// How many bytes the artifact contained
        got: usize,
    },
}

/// Error type describing things that can go wrong when operating on Wasm Memories.
#[derive(Error, Debug, Clone, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum MemoryError {
    /// Low level error with mmap.
    #[error("Error when allocating memory: {0}")]
    Region(String),
    /// The operation would cause the size of the memory to exceed the maximum or would cause
    /// an overflow leading to unindexable memory.
    #[error("The memory could not grow: current size {} pages, requested increase: {} pages", current.0, attempted_delta.0)]
    CouldNotGrow {
        /// The current size in pages.
        current: Pages,
        /// The attempted amount to grow by in pages.
        attempted_delta: Pages,
    },
    /// Invalid memory was provided.
    #[error("The memory is invalid because {}", reason)]
    InvalidMemory {
        /// The reason why the provided memory is invalid.
        reason: String,
    },
    /// Caller asked for more minimum memory than we can give them.
    #[error("The minimum requested ({} pages) memory is greater than the maximum allowed memory ({} pages)", min_requested.0, max_allowed.0)]
    MinimumMemoryTooLarge {
        /// The number of pages requested as the minimum amount of memory.
        min_requested: Pages,
        /// The maximum amount of memory we can allocate.
        max_allowed: Pages,
    },
    /// Caller asked for a maximum memory greater than we can give them.
    #[error("The maximum requested memory ({} pages) is greater than the maximum allowed memory ({} pages)", max_requested.0, max_allowed.0)]
    MaximumMemoryTooLarge {
        /// The number of pages requested as the maximum amount of memory.
        max_requested: Pages,
        /// The number of pages requested as the maximum amount of memory.
        max_allowed: Pages,
    },
    /// Returned when a shared memory is required, but the given memory is not shared.
    #[error("The memory is not shared")]
    MemoryNotShared,
    /// Returned when trying to call a memory operation that is not supported by
    /// the particular memory implementation.
    #[error("tried to call an unsupported memory operation: {message}")]
    UnsupportedOperation {
        /// Message describing the unsupported operation.
        message: String,
    },
    /// The memory does not support atomic operations.
    #[error("The memory does not support atomic operations")]
    AtomicsNotSupported,
    /// A user defined error value, used for error cases not listed above.
    #[error("A user-defined error occurred: {0}")]
    Generic(String),
}

/// An ImportError.
///
/// Note: this error is not standard to WebAssembly, but it's
/// useful to determine the import issue on the API side.
#[derive(Error, Debug, Clone)]
pub enum ImportError {
    /// Incompatible Import Type.
    /// This error occurs when the import types mismatch.
    #[error("incompatible import type. Expected {0:?} but received {1:?}")]
    IncompatibleType(ExternType, ExternType),

    /// Unknown Import.
    /// This error occurs when an import was expected but not provided.
    #[error("unknown import. Expected {0:?}")]
    UnknownImport(ExternType),

    /// Memory Error
    #[error("memory error. {0}")]
    MemoryError(String),
}

/// An error while preinstantiating a module.
///
#[derive(Error, Debug)]
pub enum PreInstantiationError {
    /// The module was compiled with a CPU feature that is not available on
    /// the current host.
    #[error("module compiled with CPU feature that is missing from host")]
    CpuFeature(String),
}

use crate::lib::std::string::String;

// Compilation Errors
//
// If `std` feature is enable, we can't use `thiserror` until
// https://github.com/dtolnay/thiserror/pull/64 is merged.

/// The WebAssembly.CompileError object indicates an error during
/// WebAssembly decoding or validation.
///
/// This is based on the [Wasm Compile Error][compile-error] API.
///
/// [compiler-error]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/CompileError
#[derive(Debug)]
#[cfg_attr(feature = "std", derive(Error))]
pub enum CompileError {
    /// A Wasm translation error occured.
    #[cfg_attr(feature = "std", error("WebAssembly translation error: {0}"))]
    Wasm(WasmError),

    /// A compilation error occured.
    #[cfg_attr(feature = "std", error("Compilation error: {0}"))]
    Codegen(String),

    /// The module did not pass validation.
    #[cfg_attr(feature = "std", error("Validation error: {0}"))]
    Validate(String),

    /// The compiler doesn't support a Wasm feature
    #[cfg_attr(feature = "std", error("Feature {0} is not yet supported"))]
    UnsupportedFeature(String),

    /// The compiler cannot compile for the given target.
    /// This can refer to the OS, the chipset or any other aspect of the target system.
    #[cfg_attr(
        feature = "std",
        error("The target {0} is not yet supported (see https://docs.wasmer.io/runtime/features)")
    )]
    UnsupportedTarget(String),

    /// Insufficient resources available for execution.
    #[cfg_attr(feature = "std", error("Insufficient resources: {0}"))]
    Resource(String),
}

impl From<WasmError> for CompileError {
    fn from(original: WasmError) -> Self {
        Self::Wasm(original)
    }
}

/// A error in the middleware.
#[derive(Debug)]
#[cfg_attr(feature = "std", derive(Error))]
#[cfg_attr(feature = "std", error("Error in middleware {name}: {message}"))]
pub struct MiddlewareError {
    /// The name of the middleware where the error was created
    pub name: String,
    /// The error message
    pub message: String,
}

impl MiddlewareError {
    /// Create a new `MiddlewareError`
    pub fn new<A: Into<String>, B: Into<String>>(name: A, message: B) -> Self {
        Self {
            name: name.into(),
            message: message.into(),
        }
    }
}

/// A WebAssembly translation error.
///
/// When a WebAssembly function can't be translated, one of these error codes will be returned
/// to describe the failure.
#[derive(Debug)]
#[cfg_attr(feature = "std", derive(Error))]
pub enum WasmError {
    /// The input WebAssembly code is invalid.
    ///
    /// This error code is used by a WebAssembly translator when it encounters invalid WebAssembly
    /// code. This should never happen for validated WebAssembly code.
    #[cfg_attr(
        feature = "std",
        error("Invalid input WebAssembly code at offset {offset}: {message}")
    )]
    InvalidWebAssembly {
        /// A string describing the validation error.
        message: String,
        /// The bytecode offset where the error occurred.
        offset: usize,
    },

    /// A feature used by the WebAssembly code is not supported by the embedding environment.
    ///
    /// Embedding environments may have their own limitations and feature restrictions.
    #[cfg_attr(feature = "std", error("Unsupported feature: {0}"))]
    Unsupported(String),

    /// An implementation limit was exceeded.
    #[cfg_attr(feature = "std", error("Implementation limit exceeded"))]
    ImplLimitExceeded,

    /// An error from the middleware error.
    #[cfg_attr(feature = "std", error("{0}"))]
    Middleware(MiddlewareError),

    /// A generic error.
    #[cfg_attr(feature = "std", error("{0}"))]
    Generic(String),
}

impl From<MiddlewareError> for WasmError {
    fn from(original: MiddlewareError) -> Self {
        Self::Middleware(original)
    }
}

/// The error that can happen while parsing a `str`
/// to retrieve a [`CpuFeature`](crate::CpuFeature).
#[derive(Debug)]
#[cfg_attr(feature = "std", derive(Error))]
pub enum ParseCpuFeatureError {
    /// The provided string feature doesn't exist
    #[cfg_attr(feature = "std", error("CpuFeature {0} not recognized"))]
    Missing(String),
}

/// A convenient alias for a `Result` that uses `WasmError` as the error type.
pub type WasmResult<T> = Result<T, WasmError>;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn middleware_error_can_be_created() {
        let msg = String::from("Something went wrong");
        let error = MiddlewareError::new("manipulator3000", msg);
        assert_eq!(error.name, "manipulator3000");
        assert_eq!(error.message, "Something went wrong");
    }

    #[test]
    fn middleware_error_be_converted_to_wasm_error() {
        let error = WasmError::from(MiddlewareError::new("manipulator3000", "foo"));
        match error {
            WasmError::Middleware(MiddlewareError { name, message }) => {
                assert_eq!(name, "manipulator3000");
                assert_eq!(message, "foo");
            }
            err => panic!("Unexpected error: {:?}", err),
        }
    }
}