From a680ab194ced4f7fd044ed45f42062581e4f26ca Mon Sep 17 00:00:00 2001
From: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Date: Fri, 21 Apr 2017 03:45:05 +0100
Subject: [PATCH] Add an Explicit Message Encryption parser.

---
 src/eme.rs | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs |  6 +++++
 src/ns.rs  |  3 +++
 3 files changed, 77 insertions(+)
 create mode 100644 src/eme.rs

diff --git a/src/eme.rs b/src/eme.rs
new file mode 100644
index 00000000..cf33de7f
--- /dev/null
+++ b/src/eme.rs
@@ -0,0 +1,68 @@
+use minidom::Element;
+
+use error::Error;
+
+use ns;
+
+#[derive(Debug, Clone)]
+pub struct ExplicitMessageEncryption {
+    pub namespace: String,
+    pub name: Option<String>,
+}
+
+pub fn parse_explicit_message_encryption(root: &Element) -> Result<ExplicitMessageEncryption, Error> {
+    if !root.is("encryption", ns::EME) {
+        return Err(Error::ParseError("This is not an encryption element."));
+    }
+    for _ in root.children() {
+        return Err(Error::ParseError("Unknown child in encryption element."));
+    }
+    let namespace = root.attr("namespace").ok_or(Error::ParseError("Mandatory argument 'namespace' not present in encryption element."))?.to_owned();
+    let name = root.attr("name").and_then(|value| value.parse().ok());
+    Ok(ExplicitMessageEncryption {
+        namespace: namespace,
+        name: name,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use minidom::Element;
+    use error::Error;
+    use eme;
+
+    #[test]
+    fn test_simple() {
+        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0' namespace='urn:xmpp:otr:0'/>".parse().unwrap();
+        let encryption = eme::parse_explicit_message_encryption(&elem).unwrap();
+        assert_eq!(encryption.namespace, "urn:xmpp:otr:0");
+        assert_eq!(encryption.name, None);
+
+        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0' namespace='some.unknown.mechanism' name='SuperMechanism'/>".parse().unwrap();
+        let encryption = eme::parse_explicit_message_encryption(&elem).unwrap();
+        assert_eq!(encryption.namespace, "some.unknown.mechanism");
+        assert_eq!(encryption.name, Some(String::from("SuperMechanism")));
+    }
+
+    #[test]
+    fn test_unknown() {
+        let elem: Element = "<replace xmlns='urn:xmpp:message-correct:0'/>".parse().unwrap();
+        let error = eme::parse_explicit_message_encryption(&elem).unwrap_err();
+        let message = match error {
+            Error::ParseError(string) => string,
+            _ => panic!(),
+        };
+        assert_eq!(message, "This is not an encryption element.");
+    }
+
+    #[test]
+    fn test_invalid_child() {
+        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0'><coucou/></encryption>".parse().unwrap();
+        let error = eme::parse_explicit_message_encryption(&elem).unwrap_err();
+        let message = match error {
+            Error::ParseError(string) => string,
+            _ => panic!(),
+        };
+        assert_eq!(message, "Unknown child in encryption element.");
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 50679604..167f58ec 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -49,6 +49,9 @@ pub mod attention;
 /// XEP-0308: Last Message Correction
 pub mod message_correct;
 
+/// XEP-0380: Explicit Message Encryption
+pub mod eme;
+
 /// XEP-0390: Entity Capabilities 2.0
 pub mod ecaps2;
 
@@ -60,6 +63,7 @@ pub enum MessagePayload {
     Receipt(receipts::Receipt),
     Attention(attention::Attention),
     MessageCorrect(message_correct::MessageCorrect),
+    ExplicitMessageEncryption(eme::ExplicitMessageEncryption),
 }
 
 /// Parse one of the payloads of a `<message/>` element, and return `Some` of a
@@ -75,6 +79,8 @@ pub fn parse_message_payload(elem: &Element) -> Option<MessagePayload> {
         Some(MessagePayload::Attention(attention))
     } else if let Ok(replace) = message_correct::parse_message_correct(elem) {
         Some(MessagePayload::MessageCorrect(replace))
+    } else if let Ok(eme) = eme::parse_explicit_message_encryption(elem) {
+        Some(MessagePayload::ExplicitMessageEncryption(eme))
     } else {
         None
     }
diff --git a/src/ns.rs b/src/ns.rs
index df708fbe..6aa1d3f7 100644
--- a/src/ns.rs
+++ b/src/ns.rs
@@ -31,6 +31,9 @@ pub const ATTENTION: &'static str = "urn:xmpp:attention:0";
 /// XEP-0308: Last Message Correction
 pub const MESSAGE_CORRECT: &'static str = "urn:xmpp:message-correct:0";
 
+/// XEP-0380: Explicit Message Encryption
+pub const EME: &'static str = "urn:xmpp:eme:0";
+
 /// XEP-0390: Entity Capabilities 2.0
 pub const ECAPS2: &'static str = "urn:xmpp:caps";
 /// XEP-0390: Entity Capabilities 2.0