add shared-lib folder

shared-lib/lib-ot/src/errors.rs

@@ -0,0 +1,72 @@
+use std::{error::Error, fmt, str::Utf8Error};
+
+#[derive(Clone, Debug)]
+pub struct OTError {
+    pub code: OTErrorCode,
+    pub msg: String,
+}
+
+impl OTError {
+    pub fn new(code: OTErrorCode, msg: &str) -> OTError {
+        Self {
+            code,
+            msg: msg.to_owned(),
+        }
+    }
+}
+
+impl fmt::Display for OTError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "incompatible lengths") }
+}
+
+impl Error for OTError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> { None }
+}
+
+impl std::convert::From<serde_json::Error> for OTError {
+    fn from(error: serde_json::Error) -> Self { ErrorBuilder::new(OTErrorCode::SerdeError).error(error).build() }
+}
+
+impl std::convert::From<Utf8Error> for OTError {
+    fn from(error: Utf8Error) -> Self { ErrorBuilder::new(OTErrorCode::SerdeError).error(error).build() }
+}
+
+#[derive(Debug, Clone)]
+pub enum OTErrorCode {
+    IncompatibleLength,
+    ApplyInsertFail,
+    ApplyDeleteFail,
+    ApplyFormatFail,
+    ComposeOperationFail,
+    IntervalOutOfBound,
+    UndoFail,
+    RedoFail,
+    SerdeError,
+}
+
+pub struct ErrorBuilder {
+    pub code: OTErrorCode,
+    pub msg: Option<String>,
+}
+
+impl ErrorBuilder {
+    pub fn new(code: OTErrorCode) -> Self { ErrorBuilder { code, msg: None } }
+
+    pub fn msg<T>(mut self, msg: T) -> Self
+    where
+        T: Into<String>,
+    {
+        self.msg = Some(msg.into());
+        self
+    }
+
+    pub fn error<T>(mut self, msg: T) -> Self
+    where
+        T: std::fmt::Debug,
+    {
+        self.msg = Some(format!("{:?}", msg));
+        self
+    }
+
+    pub fn build(mut self) -> OTError { OTError::new(self.code, &self.msg.take().unwrap_or("".to_owned())) }
+}