update quick_xml and migrate from error-chain to failure

src/error.rs

@@ -2,34 +2,51 @@
 
 use std::convert::From;
 
-error_chain! {
-    foreign_links {
-        XmlError(::quick_xml::errors::Error)
-            /// An error from quick_xml.
-        ;
-        Utf8Error(::std::str::Utf8Error)
-            /// An UTF-8 conversion error.
-        ;
-        IoError(::std::io::Error)
-            /// An I/O error, from std::io.
-        ;
-    }
+/// Our main error type.
+#[derive(Debug, Fail)]
+pub enum Error {
+    /// An error from quick_xml.
+    #[fail(display = "XML error: {}", _0)]
+    XmlError(#[cause] ::quick_xml::errors::Error),
 
-    errors {
-        /// An error which is returned when the end of the document was reached prematurely.
-        EndOfDocument {
-            description("the end of the document has been reached prematurely")
-            display("the end of the document has been reached prematurely")
-        }
-        /// An error which is returned when an element is closed when it shouldn't be
-        InvalidElementClosed {
-            description("The XML is invalid, an element was wrongly closed")
-            display("the XML is invalid, an element was wrongly closed")
-        }
-        /// An error which is returned when an elemet's name contains more than one colon
-        InvalidElement {
-            description("The XML element is invalid")
-            display("the XML element is invalid")
-        }
+    /// An UTF-8 conversion error.
+    #[fail(display = "UTF-8 error: {}", _0)]
+    Utf8Error(#[cause] ::std::str::Utf8Error),
+
+    /// An I/O error, from std::io.
+    #[fail(display = "IO error: {}", _0)]
+    IoError(#[cause] ::std::io::Error),
+
+    /// An error which is returned when the end of the document was reached prematurely.
+    #[fail(display = "the end of the document has been reached prematurely")]
+    EndOfDocument,
+
+    /// An error which is returned when an element is closed when it shouldn't be
+    #[fail(display = "the XML is invalid, an element was wrongly closed")]
+    InvalidElementClosed,
+
+    /// An error which is returned when an elemet's name contains more than one colon
+    #[fail(display = "the XML element is invalid")]
+    InvalidElement,
+}
+
+impl From<::quick_xml::errors::Error> for Error {
+    fn from(err: ::quick_xml::errors::Error) -> Error {
+        Error::XmlError(err)
     }
 }
+
+impl From<::std::str::Utf8Error> for Error {
+    fn from(err: ::std::str::Utf8Error) -> Error {
+        Error::Utf8Error(err)
+    }
+}
+
+impl From<::std::io::Error> for Error {
+    fn from(err: ::std::io::Error) -> Error {
+        Error::IoError(err)
+    }
+}
+
+/// Our simplified Result type.
+pub type Result<T> = ::std::result::Result<T, Error>;