cdrs 2.2.0

Cassandra DB driver written in Rust
Documentation 
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use std::error;
use std::fmt;
use std::fmt::Display;
use std::io;
use std::result;
use std::string::FromUtf8Error;

use crate::compression::CompressionError;
use crate::frame::frame_error::CDRSError;
use uuid::BytesError;

pub type Result<T> = result::Result<T, Error>;

/// CDRS custom error type. CDRS expects two types of error - errors returned by Server
/// and internal erros occured within the driver itself. Ocassionaly `io::Error`
/// is a type that represent internal error because due to implementation IO errors only
/// can be raised by CDRS driver. `Server` error is an error which are ones returned by
/// a Server via result error frames.
#[derive(Debug)]
pub enum Error {
  /// Internal IO error.
  Io(io::Error),
  /// Internal error that may be raised during `uuid::Uuid::from_bytes`
  UUIDParse(BytesError),
  /// General error
  General(String),
  /// Internal error that may be raised during `String::from_utf8`
  FromUtf8(FromUtf8Error),
  /// Internal Compression/Decompression error
  Compression(CompressionError),
  /// Server error.
  Server(CDRSError),
}

pub fn column_is_empty_err<T: Display>(column_name: T) -> Error {
  Error::General(format!("Column or UDT property '{}' is empty", column_name))
}

impl fmt::Display for Error {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    match *self {
      Error::Io(ref err) => write!(f, "IO error: {}", err),
      Error::Compression(ref err) => write!(f, "Compressor error: {}", err),
      Error::Server(ref err) => write!(f, "Server error: {:?}", err.message),
      Error::FromUtf8(ref err) => write!(f, "FromUtf8Error error: {:?}", err),
      Error::UUIDParse(ref err) => write!(f, "UUIDParse error: {:?}", err),
      Error::General(ref err) => write!(f, "GeneralParsing error: {:?}", err),
    }
  }
}

impl error::Error for Error {
  fn description(&self) -> &str {
    match *self {
      Error::Io(ref err) => err.description(),
      Error::Compression(ref err) => err.description(),
      Error::Server(ref err) => err.message.as_str(),
      Error::FromUtf8(ref err) => err.description(),
      // FIXME: err.description not found in current scope, std::error::Error not satisfied
      Error::UUIDParse(_) => "UUID Parse Error",
      Error::General(ref err) => err.as_str(),
    }
  }
}

impl From<io::Error> for Error {
  fn from(err: io::Error) -> Error {
    Error::Io(err)
  }
}

impl From<CDRSError> for Error {
  fn from(err: CDRSError) -> Error {
    Error::Server(err)
  }
}

impl From<CompressionError> for Error {
  fn from(err: CompressionError) -> Error {
    Error::Compression(err)
  }
}

impl From<FromUtf8Error> for Error {
  fn from(err: FromUtf8Error) -> Error {
    Error::FromUtf8(err)
  }
}

impl From<BytesError> for Error {
  fn from(err: BytesError) -> Error {
    Error::UUIDParse(err)
  }
}

impl From<String> for Error {
  fn from(err: String) -> Error {
    Error::General(err)
  }
}

impl<'a> From<&'a str> for Error {
  fn from(err: &str) -> Error {
    Error::General(err.to_string())
  }
}