Move Error, helpers and macros into a util module.

src/util/error.rs

@@ -0,0 +1,97 @@
+// Copyright (c) 2017-2018 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use base64;
+use chrono;
+use jid;
+use std::convert::From;
+use std::fmt;
+use std::net;
+use std::num;
+use std::string;
+
+/// Contains one of the potential errors triggered while parsing an
+/// [Element](../struct.Element.html) into a specialised struct.
+#[derive(Debug)]
+pub enum Error {
+    /// The usual error when parsing something.
+    ///
+    /// TODO: use a structured error so the user can report it better, instead
+    /// of a freeform string.
+    ParseError(&'static str),
+
+    /// Generated when some base64 content fails to decode, usually due to
+    /// extra characters.
+    Base64Error(base64::DecodeError),
+
+    /// Generated when text which should be an integer fails to parse.
+    ParseIntError(num::ParseIntError),
+
+    /// Generated when text which should be a string fails to parse.
+    ParseStringError(string::ParseError),
+
+    /// Generated when text which should be an IP address (IPv4 or IPv6) fails
+    /// to parse.
+    ParseAddrError(net::AddrParseError),
+
+    /// Generated when text which should be a [JID](../../jid/struct.Jid.html)
+    /// fails to parse.
+    JidParseError(jid::JidParseError),
+
+    /// Generated when text which should be a
+    /// [DateTime](../date/struct.DateTime.html) fails to parse.
+    ChronoParseError(chrono::ParseError),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Error::ParseError(s) => write!(fmt, "{}", s),
+            Error::Base64Error(ref e) => write!(fmt, "{}", e),
+            Error::ParseIntError(ref e) => write!(fmt, "{}", e),
+            Error::ParseStringError(ref e) => write!(fmt, "{}", e),
+            Error::ParseAddrError(ref e) => write!(fmt, "{}", e),
+            Error::JidParseError(_) => write!(fmt, "JID parse error"),
+            Error::ChronoParseError(ref e) => write!(fmt, "{}", e),
+        }
+    }
+}
+
+impl From<base64::DecodeError> for Error {
+    fn from(err: base64::DecodeError) -> Error {
+        Error::Base64Error(err)
+    }
+}
+
+impl From<num::ParseIntError> for Error {
+    fn from(err: num::ParseIntError) -> Error {
+        Error::ParseIntError(err)
+    }
+}
+
+impl From<string::ParseError> for Error {
+    fn from(err: string::ParseError) -> Error {
+        Error::ParseStringError(err)
+    }
+}
+
+impl From<net::AddrParseError> for Error {
+    fn from(err: net::AddrParseError) -> Error {
+        Error::ParseAddrError(err)
+    }
+}
+
+impl From<jid::JidParseError> for Error {
+    fn from(err: jid::JidParseError) -> Error {
+        Error::JidParseError(err)
+    }
+}
+
+impl From<chrono::ParseError> for Error {
+    fn from(err: chrono::ParseError) -> Error {
+        Error::ChronoParseError(err)
+    }
+}