2 files changed, 141 insertions, 0 deletions
diff --git a/src/dav/decoder.rs b/src/dav/decoder.rs
new file mode 100644
index 0000000..5996a05
--- /dev/null
+++ b/src/dav/decoder.rs
@@ -0,0 +1,140 @@
+use std::borrow::Cow;
+
+use im::HashMap;
+use quick_xml::events::{BytesStart, BytesText};
+use quick_xml::events::attributes::AttrError;
+use quick_xml::name::PrefixDeclaration;
+use quick_xml::reader::Reader;
+use tokio::io::AsyncBufRead;
+
+use super::types::*;
+
+pub enum ParsingError {
+    NamespacePrefixAlreadyUsed,
+    WrongToken,
+    QuickXml(quick_xml::Error)
+}
+impl From<AttrError> for ParsingError {
+    fn from(value: AttrError) -> Self {
+        Self::QuickXml(value.into())
+    }
+}
+impl From<quick_xml::Error> for ParsingError {
+    fn from(value: quick_xml::Error) -> Self {
+        Self::QuickXml(value)
+    }
+}
+
+const DAV_URN: &[u8] = b"DAV:";
+const CALDAV_URN: &[u8] = b"urn:ietf:params:xml:ns:caldav";
+const CARDDAV_URN: &[u8] = b"urn:ietf:params:xml:ns:carddav";
+const XML_URN: &[u8] = b"xml";
+
+#[derive(PartialEq, Clone)]
+pub enum XmlNamespace {
+    None,
+    Dav,
+    CalDav,
+    CardDav,
+    Xml,
+    Unknown(Vec<u8>),
+}
+impl From<&[u8]> for XmlNamespace {
+    fn from(value: &[u8]) -> Self {
+        match value {
+            [] => Self::None,
+            DAV_URN => Self::Dav,
+            CALDAV_URN => Self::CalDav,
+            CARDDAV_URN => Self::CardDav,
+            XML_URN => Self::Xml,
+            v => Self::Unknown(v.into()),
+        }
+    }
+}
+
+/// Context must stay cheap to clone
+/// as we are cloning it from one fonction to another
+#[derive(Clone)]
+pub struct Context<'a, E: Extension + Clone> {
+    pub aliases: HashMap<&'a [u8], XmlNamespace>,
+    phantom: std::marker::PhantomData<E>,
+}
+impl<'a, E: Extension + Clone> Context<'a, E> {
+    /// External buffer
+    pub fn new() -> Self {
+        Self { 
+            aliases: HashMap::new(),
+            phantom: std::marker::PhantomData 
+        }
+    }
+
+    pub fn ns_scan(&mut self, token: &'a BytesStart<'a>) -> Result<(XmlNamespace, &[u8]), ParsingError> {
+        // Register namespace aliases from attributes (aka namespace bindings)
+        for attr_res in token.attributes() {
+            let attr = attr_res?;
+            match attr.key.as_namespace_binding() {
+                None => (),
+                Some(PrefixDeclaration::Named(prefix)) => self.ns_alias(attr.value.as_ref(), prefix.as_ref())?,
+                Some(PrefixDeclaration::Default) => self.ns_default(attr.value.as_ref())?,
+            }
+        }
+
+        // Decompose tag name
+        let (key, maybe_prefix) = token.name().decompose();
+        let ns = self.ns_resolve(maybe_prefix.map(|p| p.into_inner()).unwrap_or(&b""[..]));
+
+        Ok((ns, key.into_inner()))
+    }
+
+    fn ns_default(&mut self, fqns: &[u8]) -> Result<(), ParsingError> {
+        self.ns_alias(fqns, &b""[..])
+    }
+
+    fn ns_alias(&mut self, fqns: &[u8], alias: &'a [u8]) -> Result<(), ParsingError> {
+        let parsed_ns = XmlNamespace::from(fqns);
+        if let Some(reg_fqns) = self.aliases.get(alias) {
+            if *reg_fqns != parsed_ns {
+                return Err(ParsingError::NamespacePrefixAlreadyUsed)
+            }
+        }
+        self.aliases.insert(alias, parsed_ns);
+        Ok(())
+    }
+
+    // If the namespace is not found in the alias table (binding table)
+    // we suppose it's a fully qualified namespace (fqns)
+    fn ns_resolve(&self, prefix: &[u8]) -> XmlNamespace {
+        match self.aliases.get(prefix) {
+            Some(fqns) => fqns.clone(),
+            None => XmlNamespace::from(prefix),
+        }
+    }
+}
+
+trait DavReader<'a> {
+    async fn doctype(&self) -> Result<(), ParsingError>;
+    async fn tag(&self) -> Result<BytesStart<'a>, ParsingError>;
+    async fn txt(&self) -> Result<Cow<'a, u8>, ParsingError>;
+}
+/*impl<'a, I: AsyncBufRead+Unpin> DavReader<'a> for Reader<I> {
+    async fn doctype(&self) -> Result<(), ParsingError> {
+    }
+    async fn tag(&self) -> Result<BytesStart<'a>, ParsingError> {
+    }
+    async fn txt(&self) -> Result<Cow<'a, u8>, ParsingError> {
+    }
+}*/
+
+pub async fn propfind<E: Extension+Clone>(
+    xml: &mut Reader<impl AsyncBufRead+Unpin>, 
+    ctx: Context<'_, E>,
+    buf: &mut Vec<u8>,
+) -> Result<PropFind<E>, ParsingError> {
+    let local = ctx.clone();
+
+    match xml.read_event_into_async(buf).await? {
+        _ => unimplemented!(),
+    }
+
+    unimplemented!();
+}
diff --git a/src/dav/mod.rs b/src/dav/mod.rs
index 4044895..835544b 100644
--- a/src/dav/mod.rs
+++ b/src/dav/mod.rs
@@ -4,6 +4,7 @@ mod acltypes;
 mod versioningtypes;
 mod encoder;
 mod calencoder;
+mod decoder;
 
 use std::net::SocketAddr;