improve error handling

crates/wit-generator/src/errors.rs

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2020 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 std::error::Error;
+use serde_json::Error as SerdeDeserializationError;
+
+#[derive(Debug)]
+pub enum WITGeneratorError {
+    /// An error related to serde deserialization.
+    DeserializationError(SerdeDeserializationError),
+
+    /// Various errors occurred during the parsing/emitting a Wasm file.
+    IOError(String),
+}
+
+impl Error for WITGeneratorError {}
+
+impl std::fmt::Display for WITGeneratorError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        match self {
+            WITGeneratorError::DeserializationError(err) => write!(
+                f,
+                "Embedded by rust-sdk metadata could't be parsed by serde: {:?}",
+                err
+            ),
+            WITGeneratorError::IOError(err) => write!(f, "I/O error occurred: {:?}", err),
+        }
+    }
+}
+
+impl From<SerdeDeserializationError> for WITGeneratorError {
+    fn from(err: SerdeDeserializationError) -> Self {
+        WITGeneratorError::DeserializationError(err)
+    }
+}