Implement variables in attributes

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

src/element.rs

@@ -38,10 +38,16 @@
 //!		<message scansion:strict="true"/>
 //! ```
 
+use std::collections::HashMap;
 use std::ops::Deref;
 use std::fmt::Debug;
 use std::marker::PhantomData;
 
+use crate::{Client, ClientName};
+use crate::types::VariableAttr;
+use crate::parsers::parse_variable;
+
+use jid::BareJid;
 use minidom::{Element, Node};
 
 /// Namespaces used for Client entities
@@ -193,25 +199,32 @@ impl PartialEq<Vec<Node>> for ScanNodes<NonStrictComparison> {
 /// changes the way the comparison is done.
 /// Also uses the custom ScanNode implementation.
 #[derive(Debug, Clone)]
-pub struct ScanElement<'a> {
+pub struct ScanElement<'a, 'b> {
     elem: &'a Element,
+    context: Option<&'b HashMap<ClientName, Client>>,
 }
 
-impl<'a> Deref for ScanElement<'a> {
-	type Target = Element;
+impl<'a, 'b> Deref for ScanElement<'a, 'b> {
+    type Target = Element;
 
 	fn deref(&self) -> &Self::Target {
 		&self.elem
 	}
 }
 
-impl<'a> ScanElement<'a> {
-	pub fn new(elem: &'a Element) -> ScanElement {
-		Self { elem }
-	}
+impl<'a> ScanElement<'a, 'static> {
+    pub fn new(elem: &'a Element) -> ScanElement {
+        Self { elem, context: None }
+    }
 }
 
-impl<'a> PartialEq<&Element> for ScanElement<'a> {
+impl <'a, 'b> ScanElement<'a, 'b> {
+    pub fn with_context(self, context: &'b HashMap<ClientName, Client>) -> ScanElement<'a, 'b> {
+        Self { elem: self.elem, context: Some(context) }
+    }
+}
+
+impl<'a, 'b> PartialEq<&Element> for ScanElement<'a, 'b> {
 	fn eq(&self, other: &&Element) -> bool {
 		let self_ns = self.elem.ns();
 		if self.elem.name() == other.name() &&
@@ -231,6 +244,28 @@ impl<'a> PartialEq<&Element> for ScanElement<'a> {
                     continue;
                 }
 
+                // Parse variables. If parsing fails, continue attr comparison.
+                // If context isn't set, skip this and continue attr comparison.
+                if let Ok((_, var)) = parse_variable(val.into()) &&
+                   let Some(context) = self.context {
+                    let res = match var {
+                        VariableAttr::FullJid(name) => match context.get(&name) {
+                           Some(Client { jid, .. }) => String::from(jid.clone()),
+                           _ => return false,
+                        },
+                        VariableAttr::BareJid(name) => match context.get(&name) {
+                           Some(Client { jid, .. }) => String::from(BareJid::from(jid.clone())),
+                           _ => return false,
+                        },
+                    };
+
+                    if let Some(oval) = other.attr(attr) && res == oval {
+                        continue;
+                    } else {
+                        return false;
+                    }
+                }
+
                 match (attr, other.attr(attr)) {
                     (attr, _) if attr == "scansion:strict" => continue,
                     (_, None) => return false,
@@ -493,4 +528,22 @@ mod tests {
 
         assert_eq!(scan1, &elem2);
     }
+
+    #[test]
+    fn variables_from_context() {
+        let louise = Client::new(Jid::from_str("louise@example.com").unwrap(), "passwd");
+
+        let clients = {
+            let mut tmp = HashMap::new();
+            tmp.insert(String::from("louise"), louise);
+            tmp
+        };
+
+        let elem1: Element = "<message xmlns='foo' to=\"${louise's full JID}\" />"
+            .parse().unwrap();
+        let elem2: Element = "<message xmlns='foo' to='louise@example.com' />".parse().unwrap();
+        let scan1 = ScanElement::new(&elem1).with_context(&clients);
+
+        assert_eq!(scan1, &elem2);
+    }
 }

src/lib.rs

@@ -4,10 +4,12 @@
 // 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/.
 
+#![feature(let_chains)]
+
 pub mod element;
 pub mod parsers;
 pub mod types;
 
 pub use element::ScanElement;
 pub use parsers::parse_spec;
-pub use types::{Action, Client, Metadata, Spec};
+pub use types::{Action, Client, ClientName, Metadata, Spec};

src/parsers.rs

@@ -4,7 +4,7 @@
 // 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 crate::types::{Action, Client, ClientName, Metadata, Spec};
+use crate::types::{Action, Client, ClientName, Metadata, VariableAttr, Spec};
 
 use std::collections::HashMap;
 use std::str::FromStr;
@@ -279,6 +279,25 @@ pub fn parse_spec(i: &str) -> Result<Spec, Token> {
 	})
 }
 
+pub fn parse_variable(s: Span) -> IResult<Span, VariableAttr> {
+    let (s, (_, name, attr, _)) = tuple((
+        tag("${"), take_until_tags(vec![
+                "'s full JID",
+                "'s JID",
+            ].into_iter(),
+            "}",
+        ),
+        alt((tag("'s full JID"), tag("'s JID"))),
+        tag("}"),
+    ))(s)?;
+
+    Ok((s, match *attr.fragment() {
+        "'s full JID" => VariableAttr::FullJid(name.to_string()),
+        "'s JID" => VariableAttr::BareJid(name.to_string()),
+        _ => unreachable!(),
+    }))
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -602,4 +621,29 @@ louise receives:
 			})
 		);
 	}
+
+    #[test]
+    fn parse_variable_attr() {
+        let buf1: Span = "${louise's full JID}".into();
+        let buf2: Span = "${louise's JID}".into();
+        let buf3: Span = "${louise's JID".into();
+
+        assert_eq!(
+            parse_variable(buf1).unwrap().1,
+            VariableAttr::FullJid(String::from("louise")),
+        );
+
+        assert_eq!(
+            parse_variable(buf2).unwrap().1,
+            VariableAttr::BareJid(String::from("louise")),
+        );
+
+        match parse_variable(buf3) {
+            Err(nom::Err::Error(nom::error::Error { input, .. })) => {
+                assert_eq!(input.location_offset(), 2);
+                assert_eq!(input.location_line(), 1);
+            }
+            err => panic!("Expected Err, found: {err:?}"),
+        }
+    }
 }

src/types.rs

@@ -8,6 +8,12 @@ use std::collections::HashMap;
 
 use jid::Jid;
 
+#[derive(Debug, PartialEq)]
+pub enum VariableAttr {
+    FullJid(ClientName),
+    BareJid(ClientName),
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct Metadata {
 	pub title: String,