delay: Switch to Into/TryFrom.

src/delay.rs

@@ -4,7 +4,9 @@
 // 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 minidom::{Element, IntoElements, ElementEmitter};
+use std::convert::TryFrom;
+
+use minidom::Element;
 
 use error::Error;
 use jid::Jid;
@@ -18,54 +20,50 @@ pub struct Delay {
     pub data: Option<String>,
 }
 
-pub fn parse_delay(root: &Element) -> Result<Delay, Error> {
-    if !root.is("delay", ns::DELAY) {
-        return Err(Error::ParseError("This is not a delay element."));
+impl<'a> TryFrom<&'a Element> for Delay {
+    type Error = Error;
+
+    fn try_from(elem: &'a Element) -> Result<Delay, Error> {
+        if !elem.is("delay", ns::DELAY) {
+            return Err(Error::ParseError("This is not a delay element."));
+        }
+        for _ in elem.children() {
+            return Err(Error::ParseError("Unknown child in delay element."));
+        }
+        let from = elem.attr("from").and_then(|value| value.parse().ok());
+        let stamp = elem.attr("stamp").ok_or(Error::ParseError("Mandatory argument 'stamp' not present in delay element."))?.to_owned();
+        let data = match elem.text().as_ref() {
+            "" => None,
+            text => Some(text.to_owned()),
+        };
+        Ok(Delay {
+            from: from,
+            stamp: stamp,
+            data: data,
+        })
     }
-    for _ in root.children() {
-        return Err(Error::ParseError("Unknown child in delay element."));
-    }
-    let from = root.attr("from").and_then(|value| value.parse().ok());
-    let stamp = root.attr("stamp").ok_or(Error::ParseError("Mandatory argument 'stamp' not present in delay element."))?.to_owned();
-    let data = match root.text().as_ref() {
-        "" => None,
-        text => Some(text.to_owned()),
-    };
-    Ok(Delay {
-        from: from,
-        stamp: stamp,
-        data: data,
-    })
 }
 
-pub fn serialise(delay: &Delay) -> Element {
-    Element::builder("delay")
-            .ns(ns::DELAY)
-            .attr("from", delay.from.clone().and_then(|value| Some(String::from(value))))
-            .attr("stamp", delay.stamp.clone())
-            .append(delay.data.clone())
-            .build()
-}
-
-impl IntoElements for Delay {
-    fn into_elements(self, emitter: &mut ElementEmitter) {
-        let elem = serialise(&self);
-        emitter.append_child(elem)
+impl<'a> Into<Element> for &'a Delay {
+    fn into(self) -> Element {
+        Element::builder("delay")
+                .ns(ns::DELAY)
+                .attr("from", self.from.clone().and_then(|value| Some(String::from(value))))
+                .attr("stamp", self.stamp.clone())
+                .append(self.data.clone())
+                .build()
     }
 }
 
 #[cfg(test)]
 mod tests {
     use std::str::FromStr;
-    use minidom::Element;
-    use error::Error;
-    use jid::Jid;
-    use delay;
+    use super::*;
 
     #[test]
     fn test_simple() {
         let elem: Element = "<delay xmlns='urn:xmpp:delay' from='capulet.com' stamp='2002-09-10T23:08:25Z'/>".parse().unwrap();
-        let delay = delay::parse_delay(&elem).unwrap();
+        let delay = Delay::try_from(&elem).unwrap();
         assert_eq!(delay.from, Some(Jid::from_str("capulet.com").unwrap()));
         assert_eq!(delay.stamp, "2002-09-10T23:08:25Z");
         assert_eq!(delay.data, None);
@@ -74,7 +72,7 @@ mod tests {
     #[test]
     fn test_unknown() {
         let elem: Element = "<replace xmlns='urn:xmpp:message-correct:0'/>".parse().unwrap();
-        let error = delay::parse_delay(&elem).unwrap_err();
+        let error = Delay::try_from(&elem).unwrap_err();
         let message = match error {
             Error::ParseError(string) => string,
             _ => panic!(),
@@ -85,7 +83,7 @@ mod tests {
     #[test]
     fn test_invalid_child() {
         let elem: Element = "<delay xmlns='urn:xmpp:delay'><coucou/></delay>".parse().unwrap();
-        let error = delay::parse_delay(&elem).unwrap_err();
+        let error = Delay::try_from(&elem).unwrap_err();
         let message = match error {
             Error::ParseError(string) => string,
             _ => panic!(),
@@ -96,24 +94,24 @@ mod tests {
     #[test]
     fn test_serialise() {
         let elem: Element = "<delay xmlns='urn:xmpp:delay' stamp='2002-09-10T23:08:25Z'/>".parse().unwrap();
-        let delay = delay::Delay {
+        let delay = Delay {
             from: None,
             stamp: "2002-09-10T23:08:25Z".to_owned(),
             data: None,
         };
-        let elem2 = delay::serialise(&delay);
+        let elem2 = (&delay).into();
         assert_eq!(elem, elem2);
     }
 
     #[test]
     fn test_serialise_data() {
         let elem: Element = "<delay xmlns='urn:xmpp:delay' from='juliet@example.org' stamp='2002-09-10T23:08:25Z'>Reason</delay>".parse().unwrap();
-        let delay = delay::Delay {
+        let delay = Delay {
             from: Some(Jid::from_str("juliet@example.org").unwrap()),
             stamp: "2002-09-10T23:08:25Z".to_owned(),
             data: Some(String::from("Reason")),
         };
-        let elem2 = delay::serialise(&delay);
+        let elem2 = (&delay).into();
         assert_eq!(elem, elem2);
     }
 }