feat!: decouple wasmer from Marine, replace it with generic backend interface (#219)

crates/wasm-backend-traits/src/errors.rs

@@ -0,0 +1,145 @@
+/*
+ * Copyright 2023 Fluence Labs Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use crate::WType;
+
+use thiserror::Error;
+
+pub type WasmBackendResult<T> = Result<T, WasmBackendError>;
+pub type ResolveResult<T> = Result<T, ResolveError>;
+pub type RuntimeResult<T> = Result<T, RuntimeError>;
+pub type ModuleCreationResult<T> = Result<T, ModuleCreationError>;
+pub type InstantiationResult<T> = Result<T, InstantiationError>;
+pub type WasiResult<T> = Result<T, WasiError>;
+
+/*
+   General error design goals:
+       * expose as much detail as possible
+       * make as much domain-specific errors as possible implementation-independent
+
+   So, Error enums should follow this principle:
+       * errors fully expressible without implementation info should have implementation-independent view
+       * errors not fully expressible without implementation info should have some common view and a way to get implmententation-specific details
+       * "Other" type for all errors not suited for listed options
+*/
+
+#[derive(Debug, Error)]
+pub enum WasmBackendError {
+    #[error(transparent)]
+    ResolveError(#[from] ResolveError),
+
+    #[error(transparent)]
+    RuntimeError(#[from] RuntimeError),
+
+    #[error(transparent)]
+    ModuleCreationError(#[from] ModuleCreationError),
+
+    #[error(transparent)]
+    ImportError(#[from] ImportError),
+
+    #[error(transparent)]
+    InstantiationError(#[from] InstantiationError),
+
+    #[error(transparent)]
+    InitializationError(anyhow::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum ResolveError {
+    #[error("export not found: {0}")]
+    ExportNotFound(String),
+
+    #[error("export type mismatch: expected {expected}, found {actual}")]
+    ExportTypeMismatch {
+        expected: &'static str,
+        actual: &'static str,
+    },
+
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum RuntimeError {
+    #[error("Unsupported type encountered: {0}")]
+    UnsupportedType(WType),
+
+    #[error(transparent)]
+    Trap(anyhow::Error),
+
+    #[error(transparent)]
+    UserError(#[from] UserError),
+
+    #[error("A function returned invalid number of results: expected {expected}, got {actual}")]
+    IncorrectResultsNumber { expected: usize, actual: usize },
+
+    #[error(transparent)]
+    Other(anyhow::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum ModuleCreationError {
+    #[error(transparent)]
+    FailedToCompileWasm(anyhow::Error),
+
+    #[error("{0}")]
+    FailedToExtractCustomSections(String), // TODO: use a proper error type
+
+    #[error(transparent)]
+    Other(anyhow::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum ImportError {
+    #[error("Duplicate import")]
+    DuplicateImport(String, String),
+
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum InstantiationError {
+    #[error(transparent)]
+    RuntimeError(RuntimeError),
+
+    #[error(transparent)]
+    Other(#[from] anyhow::Error),
+}
+
+#[derive(Debug, Error)]
+pub enum WasiError {
+    #[error(transparent)]
+    IOError(#[from] std::io::Error),
+
+    #[error(transparent)]
+    EngineWasiError(#[from] anyhow::Error),
+
+    #[error("Cumulative size of args array exceeds 2^32")]
+    TooLargeArgsArray,
+
+    #[error("Cumulative size of envs array exceeds 2^32")]
+    TooLargeEnvsArray,
+}
+
+#[derive(Debug, Error)]
+pub enum UserError {
+    #[error(transparent)]
+    Recoverable(anyhow::Error),
+
+    #[error(transparent)]
+    Unrecoverable(anyhow::Error),
+}