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use std::error::Error; use std::fmt::{Display, Error as FmtError, Formatter}; use std::string::FromUtf8Error; use protocol_common::error::EnumValueOutOfRangeError; #[derive(Copy, Clone, Debug)] pub enum FieldName { Name(&'static str), Index(usize), } #[derive(Copy, Clone, Debug)] pub struct FieldSpec { pub field: FieldName, pub ty: Option<&'static str>, } #[derive(Debug)] pub enum SerializeErrorType { ArrayTooLarge(usize), InvalidFlagId(u16), } #[derive(Debug)] pub enum DeserializeErrorType { UnexpectedEndOfMessage, Utf8Error(FromUtf8Error), InvalidEnumValue(usize), } #[derive(Debug)] pub struct SerializeError { pub ty: SerializeErrorType, pub trace: Vec<FieldSpec>, } #[derive(Debug)] pub struct DeserializeError { pub ty: DeserializeErrorType, pub trace: Vec<FieldSpec>, } impl Display for SerializeErrorType { fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> { use SerializeErrorType::*; match self { ArrayTooLarge(size) => write!( fmt, "Array too large. This type of array can have at most {size} elements.", size = size ), InvalidFlagId(id) => write!( fmt, "Flags may only take on ids less than 255. Flag had an id of {id}.", id = id ), } } } impl Display for DeserializeErrorType { fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> { use DeserializeErrorType::*; match self { UnexpectedEndOfMessage => { write!( fmt, "Reached the end of the buffer before deserialization was complete!" ) }, Utf8Error(e) => { write!( fmt, "A string contained invalid UTF-8. Inner error: {}", e ) }, InvalidEnumValue(v) => { write!( fmt, "Attempted to deserialize an enum with an invalid value. {} does not deserialize to an enum case.", v ) } } } } fn display_trace(trace: &[FieldSpec], fmt: &mut Formatter) -> Result<(), FmtError> { for spec in trace.iter().rev() { match spec.field { FieldName::Name(field) => writeln!( fmt, "\tat {ty}::{field},", ty = spec.ty.unwrap_or("<unnamed>"), field = field )?, FieldName::Index(i) => writeln!(fmt, "\tat index ${idx},", idx = i)?, } } Ok(()) } impl Display for SerializeError { fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> { writeln!(fmt, "{}", self.ty)?; display_trace(&self.trace, fmt) } } impl Display for DeserializeError { fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> { writeln!(fmt, "{}", self.ty)?; display_trace(&self.trace, fmt) } } impl Error for SerializeError {} impl Error for DeserializeError { fn cause(&self) -> Option<&Error> { use DeserializeErrorType::*; match self.ty { Utf8Error(ref e) => Some(e), _ => None, } } } impl From<FromUtf8Error> for DeserializeError { fn from(e: FromUtf8Error) -> Self { Self { ty: DeserializeErrorType::Utf8Error(e), trace: vec![], } } } impl From<EnumValueOutOfRangeError<u8>> for DeserializeError { fn from(e: EnumValueOutOfRangeError<u8>) -> Self { Self { ty: DeserializeErrorType::InvalidEnumValue(e.0 as usize), trace: vec![], } } } impl From<EnumValueOutOfRangeError<u16>> for DeserializeError { fn from(e: EnumValueOutOfRangeError<u16>) -> Self { Self { ty: DeserializeErrorType::InvalidEnumValue(e.0 as usize), trace: vec![], } } } impl From<!> for DeserializeError { fn from(never: !) -> Self { never } } impl From<!> for SerializeError { fn from(never: !) -> Self { never } } fn append_to<T>(mut v: Vec<T>, elem: T) -> Vec<T> { v.push(elem); v } pub trait ChainError<T> { fn chain(self, elem: T) -> Self; } impl<T, E, U> ChainError<U> for Result<T, E> where E: ChainError<U>, { fn chain(self, elem: U) -> Self { self.map_err(move |e| e.chain(elem)) } } impl ChainError<FieldSpec> for SerializeError { fn chain(self, elem: FieldSpec) -> Self { Self { trace: append_to(self.trace, elem), ..self } } } impl ChainError<FieldSpec> for DeserializeError { fn chain(self, elem: FieldSpec) -> Self { Self { trace: append_to(self.trace, elem), ..self } } }